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the banker ' s gain of a certain sum due 3 years hence at 10 % per annum is rs . 36 . what is the present worth ?
[ "rs . 400", "rs . 300", "rs . 500", "rs . 350", "none of these" ]
A
"explanation : t = 3 years r = 10 % td = ( bg × 100 ) / tr = ( 36 × 100 ) / ( 3 × 10 ) = 12 × 10 = rs . 120 td = ( pw × tr ) / 100 ⇒ 120 = ( pw × 3 × 10 ) / 100 ⇒ 1200 = pw × 3 pw = 1200 / 3 = rs . 400 answer : option a"
average age of students of an adult school is 40 years . 120 new students whose average age is 32 years joined the school . as a result the average age is decreased by 4 years . find the number of students of the school after joining of the new students .
[ "1200", "120", "360", "240", "none of these" ]
D
"explanation : let the original no . of students be x . according to situation , 40 x + 120 * 32 = ( x + 120 ) 36 ⇒ x = 120 so , required no . of students after joining the new students = x + 120 = 240 . answer : d"
sophia finished 2 / 3 of a book . she calculated that she finished 90 more pages than she has yet to read . how long is her book ?
[ "229", "270", "877", "266", "281" ]
B
let xx be the total number of pages in the book , then she finished 23 ⋅ x 23 ⋅ x pages . then she has x − 23 ⋅ x = 13 ⋅ xx − 23 ⋅ x = 13 ⋅ x pages left . 23 ⋅ x − 13 ⋅ x = 9023 ⋅ x − 13 ⋅ x = 90 13 ⋅ x = 9013 ⋅ x = 90 x = 270 x = 270 so the book is 270 pages long . answer : b
120 is what percent of 50 ?
[ "5 %", "240 %", "50 %", "2 %", "500 %" ]
B
"50 * x = 120 - - > x = 2.4 - - > 2.4 expressed as percent is 240 % . answer : b ."
there are 10 girls and 20 boys in a classroom . what is the ratio of girls to boys ?
[ "1 / 2", "1 / 3", "1 / 5", "10 / 30", "2 / 5" ]
A
if girls is 10 and boys is 20 , then 10 / 20 . so ratio of girls to boys is = 10 / 20 = 1 / 2 answer : a
an empty fuel tank with a capacity of 218 gallons was filled partially with fuel a and then to capacity with fuel b . fuel a contains 12 % ethanol by volume and fuel b contains 16 % ethanol by volume . if the full fuel tank contains 30 gallons of ethanol , how many gallons of fuel a were added ?
[ "122", "150", "100", "80", "50" ]
A
"say there are a gallons of fuel a in the tank , then there would be 218 - a gallons of fuel b . the amount of ethanol in a gallons of fuel a is 0.12 a ; the amount of ethanol in 218 - a gallons of fuel b is 0.16 ( 218 - a ) ; since the total amount of ethanol is 30 gallons then 0.12 a + 0.16 ( 218 - a ) = 30 - - > a = 122 . answer : a ."
an article is bought for rs . 823 and sold for rs . 1000 , find the gain percent ?
[ "21.4 %", "21.5 %", "21.6 %", "21.7 %", "21.8 %" ]
B
"823 - - - - 177 100 - - - - ? = > 21.5 % answer : b"
6 workers should finish a job in 8 days . after 3 days came 4 workers join them . how many days m do they need to finish the same job ?
[ "3", "4", "5", "6", "7" ]
A
"let rate of one worker be r = > ( 6 * r ) * 8 = 1 ( rate * time = work ) = > r = 1 / 48 = > work remaining after 3 days 1 - ( 3 * 6 ) / 48 = 30 / 48 after 4 ppl joined in ( ( 6 + 4 ) * time ) / 48 = 30 / 48 time m = 3 days to finish the task imo a"
j is 25 % less than p and 20 % less than t . t is q % less than p . what is the value of q ?
[ "93.5", "90", "6.75", "6.25", "2" ]
D
"usually we can solve every question of this type by choosing appropriate value of the variable and deriving the value of other related variables . let , p = 400 then j = ( 75 / 100 ) * 400 = 300 also j = ( 80 / 100 ) * t i . e . t = 300 * 100 / 80 = 375 and t = [ 1 - ( q / 100 ) ] * p i . e . 100 - q = 100 * t / p = 100 * 375 / 400 = 93.75 i . e . q = 6.25 answer : option d"
a student was asked to find 4 / 5 of a number . but the student divided the number by 4 / 5 , thus the student got 36 more than the correct answer . find the number .
[ "60", "70", "80", "90", "100" ]
C
"let the number be x . ( 5 / 4 ) * x = ( 4 / 5 ) * x + 36 25 x = 16 x + 720 9 x = 720 x = 80 the answer is c ."
the average weight of 8 person ' s increases by 1.5 kg when a new person comes in place of one of them weighing 75 kg . what might be the weight of the new person ?
[ "81 kg", "85 kg", "90 kg", "100 kg", "110 kg" ]
A
"total weight increased = ( 8 x 1.5 ) kg = 6 kg . weight of new person = ( 75 + 6 ) kg = 81 kg . answer : a"
a train 125 m long passes a man , running at 15 km / hr in the same direction in which the train is going , in 10 seconds . the speed of the train is ?
[ "60", "50", "28", "26", "29" ]
A
"speed of the train relative to man = ( 125 / 10 ) m / sec = ( 25 / 2 ) m / sec . [ ( 25 / 2 ) * ( 18 / 5 ) ] km / hr = 45 km / hr . let the speed of the train be x km / hr . then , relative speed = ( x - 15 ) km / hr . x - 15 = 45 = = > x = 60 km / hr answer : a"
the average of 15 result is 60 . average of the first 10 of them is 10 and that of the last 10 is 80 . find the 8 th result ?
[ "35", "200", "150", "250", "300" ]
B
"sum of all the 13 results = 15 * 60 = 900 sum of the first 7 of them = 10 * 10 = 100 sum of the last 7 of them = 10 * 80 = 800 so , the 8 th number = 900 + 100 - 800 = 200 . b"
a salesman â € ™ s terms were changed from a flat commission of 5 % on all his sales to a fixed salary of rs . 1000 plus 2.5 % commission on all sales exceeding rs . 4,000 . if his remuneration as per new scheme was rs . 500 more than that by the previous schema , his sales were worth ?
[ "s . 14,000", "s . 12,000", "s . 16,000", "s . 40,000", "s . 50,000" ]
C
"[ 1000 + ( x - 4000 ) * ( 2.5 / 100 ) ] - x * ( 5 / 100 ) = 600 x = 16000 answer : c"
a rectangular floor that measures 15 meters by 18 meters is to be covered with carpet squares that each measure 3 meters by 3 meters . if the carpet squares cost $ 12 apiece , what is the total cost for the number of carpet squares needed to cover the floor ?
[ "$ 200", "$ 240", "$ 360", "$ 960", "$ 1,920" ]
C
"the width of the rectangular floor ( 15 m ) is a multiple of one side of the square ( 3 m ) , and the length of the floor ( 18 m ) is also a multiple of the side of the square . so the number of carpets to cover the floor is ( 15 / 3 ) * ( 18 / 3 ) = 30 . the total cost is 30 * 12 = $ 360 . the answer is , therefore , c ."
a vessel of capacity 2 litre has 30 % of alcohol and another vessel of capacity 6 litre had 40 % alcohol . the total liquid of 8 litre was poured out in a vessel of capacity 10 litre and thus the rest part of the vessel was filled with the water . what is the new concentration of mixture ?
[ "30 % .", "71 % .", "49 % .", "29 % .", "51 % ." ]
A
"30 % of 2 litres = 0.6 litres 40 % of 6 litres = 2.4 litres therefore , total quantity of alcohol is 3.0 litres . this mixture is in a 10 litre vessel . hence , the concentration of alcohol in this 10 litre vessel is 30 % answer : a"
the total of 324 of 20 paise and 25 paise make a sum of rs . 70 . the no of 20 paise coins is
[ "238", "277", "220", "200", "288" ]
C
"explanation : let the number of 20 paise coins be x . then the no of 25 paise coins = ( 324 - x ) . 0.20 * ( x ) + 0.25 ( 324 - x ) = 70 = > x = 220 . . answer : c ) 220"
in 1970 there were 8,902 women stockbrokers in the united states . by 1978 the number had increased to 18,947 . approximately what was the percent increase ?
[ "45 %", "113 %", "145 %", "150 %", "225 %" ]
B
"the percent increase is ( 18947 - 8902 ) / 8902 = 10045 / 8902 = 1.13 so the approximate answer is b"
what is the number of integers from 1 to 1100 ( inclusive ) that are divisible by neither 11 nor by 35 ?
[ "884", "890", "892", "910", "945" ]
E
"normally , i would use the method used by bunuel . it ' s the most accurate . but if you are looking for a speedy solution , you can use another method which will sometimes give you an estimate . looking at the options ( most of them are spread out ) , i wont mind trying it . ( mind you , the method is accurate here since the numbers start from 1 . ) in 1000 consecutive numbers , number of multiples of 11 = 1000 / 11 = 90 ( ignore decimals ) in 1000 consecutive numbers , number of multiples of 35 = 1000 / 35 = 28 number of multiples of 11 * 35 i . e . 385 = 1000 / 385 = 2 number of integers from 1 to 1000 that are divisible by neither 11 nor by 35 = 1000 - ( 90 + 28 - 2 ) { using the concept of sets here ) = 945 think : why did i say the method is approximate in some cases ? think what happens if the given range is 11 to 1010 both inclusive ( again 1000 numbers ) what is the number of multiples in this case ? e"
arun makes a popular brand of ice cream in a rectangular shaped bar 6 cm long , 5 cm wide and 2 cm thick . to cut costs , the company had decided to reduce the volume of the bar by 19 % . the thickness will remain same , but the length and width will be decreased by some percentage . the new width will be ,
[ "33", "87", "99", "367", "72" ]
A
answer : a
kim finds a 5 - meter tree branch and marks it off in thirds and fifths . she then breaks the branch along all the markings and removes one piece of every distinct length . what fraction of the original branch remains ?
[ "8 / 15", "1 / 2", "7 / 5", "3 / 5", "7 / 5" ]
D
"3 pieces of 1 / 5 length and two piece each of 1 / 15 and 2 / 15 lengths . removing one piece each from pieces of each kind of lengths the all that will remain will be 2 pieces of 1 / 5 i . e 2 / 5 , 1 piece of 1 / 15 , and 1 piece of 2 / 15 which gives us 2 / 5 + 1 / 15 + 2 / 15 - - - - - > 3 / 5 answer is d"
mark bought a set of 6 flower pots of different sizes at a total cost of $ 8.25 . each pot cost 0.1 more than the next one below it in size . what was the cost , in dollars , of the largest pot ?
[ "$ 1.62", "$ 1.85", "$ 2.00", "$ 2.15", "$ 2.30" ]
A
"this question can be solved with a handful of different algebra approaches ( as has been shown in the various posts ) . since the question asks for the price of the largest pot , and the answers are prices , we can test the answers . we ' re told that there are 6 pots and that each pot costs 25 cents more than the next . the total price of the pots is $ 8.25 . we ' re asked for the price of the largest ( most expensive ) pot . since the total price is $ 8.25 ( a 10 - cent increment ) and the the difference in sequential prices of the pots is 10 cents , the largest pot probably has a price that is a 10 - cent increment . from the answer choices , i would then test answer a first if . . . . the largest pot = $ 1.625 1.125 1.225 1.325 1.425 1.525 1.625 total = $ 8.25 so this must be the answer . a"
in the above number , a and b represent the tens and units digits , respectively . if the above number is divisible by 45 , what is the greatest possible value of b x a ?
[ "0", "5", "10", "15", "20" ]
E
"i also was confused when i was looking forabove number : d as far as i understood , 45 is a factor of ab . in other words , the values of b ( units digits can be 5 or 0 . better to have option for 5 in this case to havebigger result ) . now let ' s try 45 x 1 ( a = 4 , b = 5 respectively we have = 20 ) . this is the greatest possible value of b x a . imo e ."
the profit obtained by selling an article for rs . 57 is the same as the loss obtained by selling it for rs . 43 . what is the cost price of the article ?
[ "rs . 40", "rs . 50", "rs . 49", "rs . 59", "none of these" ]
B
"s . p 1 - c . p = c . p – s . p 2 57 - c . p = c . p - 43 2 c . p = 57 + 43 ; c . p = 100 / 2 = 50 answer : b"
in 2008 , the profits of company n were 8 percent of revenues . in 2009 , the revenues of company n fell by 20 percent , but profits were 15 percent of revenues . the profits in 2009 were what percent of the profits in 2008 ?
[ "150 %", "105 %", "120 %", "124.2 %", "138 %" ]
A
"the profit 0 f 2009 interms of 2008 = 0.8 * 15 / 8 * 100 = 150 % a"
a garrison of 2000 men has provisions for 54 days . at the end of 15 days , a reinforcement arrives , and it is now found that the provisions will last only for 20 days more . what is the reinforcement ?
[ "1778", "1682", "9178", "1900", "1782" ]
D
"2000 - - - - 54 2000 - - - - 39 x - - - - - 20 x * 20 = 2000 * 39 x = 3900 2000 - - - - - - - 1900 answer : d"
if a bicyclist in motion increases his speed by 30 percent and then increases this speed by 10 percent , what percent of the original speed is the total increase in speed ?
[ "10 %", "40 %", "43 %", "64 %", "140 %" ]
C
let the sped be 100 an increase of 30 % the speed now is 130 a further increase of 10 % on 130 = 13 total increase = 43 on 100 = 43 % c
what is the greatest number that divides 263 , 935 and 1383 leaving a remainder of 7 in each case ?
[ "30", "31", "32", "35", "37" ]
C
answer the required greatest number is the hcf of 263 - 7 , 935 - 7 , 1383 - 7 i . e . 256 , 928 and 1376 hcf = 32 correct option : c
how many seconds will a 900 meter long train moving with a speed of 63 km / hr take to cross a man walking with a speed of 3 km / hr in the direction of the train ?
[ "48", "36", "54", "11", "18" ]
C
"explanation : here distance d = 900 mts speed s = 63 - 3 = 60 kmph = 60 x 5 / 18 m / s time t = = 54 sec . answer : c"
find the average of all the numbers between 6 and 38 which are divisible by 4 .
[ "18", "22", "20", "30", "28" ]
B
"solution average = ( ( 8 + 12 + 16 + 20 + 24 + 28 + 32 + 36 ) / 8 ) = 186 / 7 = 22 answer b"
if the cost price is 96 % of sp then what is the profit %
[ "4.07 %", "4 %", "4.7 %", "4.17 %", "4.27 %" ]
D
"sol . sp = rs 100 : then cp = rs 96 : profit = rs 4 . profit = { ( 4 / 96 ) * 100 } % = 4.17 % answer is d ."
a car gets 27 miles to the gallon . if it is modified to use a solar panel , it will use only 75 percent as much fuel as it does now . if the fuel tank holds 14 gallons , how many more miles will the car be able to travel , per full tank of fuel , after it has been modified ?
[ "120", "126", "132", "138", "144" ]
B
"originally , the distance the car could go on a full tank was 14 * 27 = 378 miles . after it has been modified , the car can go 27 / 0.75 = 36 miles per gallon . on a full tank , the car can go 14 * 36 = 504 miles , thus 126 miles more . the answer is b ."
a fort had provision of food for 150 men for 45 days . after 10 days , 25 men left the fort . the number of days for which the remaining food will last , is :
[ "34", "387", "42", "28", "71" ]
C
"explanation : after 10 days : 150 men had food for 35 days . suppose 125 men had food for x days . now , less men , more days ( indirect proportion ) { \ color { blue } \ therefore } 125 : 150 : : 35 : x { \ color { blue } \ rightarrow } 125 x x = 150 x 35 { \ color { blue } \ rightarrow x = \ frac { 150 \ times 35 } { 125 } } { \ color { blue } \ rightarrow } x = 42 . answer : c ) 42"
a person lent a certain sum of money at 4 % per annum at simple interest and in 8 years the interest amounted to rs . 306 less than the sum lent . what was the sum lent ?
[ "228", "278", "289", "500", "450" ]
E
"p - 306 = ( p * 4 * 8 ) / 100 p = 450 answer : e"
a man has some hens and cows . if the number of heads be 50 and the number of feet equals 144 , then the number of hens will be
[ "22", "24", "26", "20", "28" ]
E
"explanation : let number of hens = h and number of cows = c number of heads = 50 = > h + c = 48 - - - ( equation 1 ) number of feet = 144 = > 2 h + 4 c = 144 = > h + 2 c = 72 - - - ( equation 2 ) ( equation 2 ) - ( equation 1 ) gives 2 c - c = 72 - 50 = > c = 22 substituting the value of c in equation 1 , we get h + 22 = 50 = > h = 50 - 22 = 28 i . e . , number of hens = 28 answer : e"
because he ’ s taxed by his home planet , mork pays a tax rate of 40 % on his income , while mindy pays a rate of only 30 % on hers . if mindy earned 3 times as much as mork did , what was their combined tax rate ?
[ "32.5 %", "34 %", "35 %", "36 %", "37.5 %" ]
A
"say morks income is - 100 so tax paid will be 40 say mindy ' s income is 3 * 100 = 300 so tax paid is 30 % * 300 = 90 total tax paid = 40 + 90 = 130 . combined tax % will be 130 / 100 + 300 = 32.5 % answer : a"
a watch was sold at a loss of 5 % . if it was sold for rs . 500 more , there would have been a gain of 5 % . what is the cost price ?
[ "1000", "2998", "2778", "2788", "2991" ]
D
"95 % 105 % - - - - - - - - 10 % - - - - 500 100 % - - - - ? = > rs . 5000 answer : d"
a car travels at a speed of 65 miles per hour . how far will it travel in 6 hours ?
[ "125 miles", "225 miles", "390 miles", "425 miles", "525 miles" ]
C
"during each hour , the car travels 65 miles . for 6 hours it will travel 65 + 65 + 65 + 65 + 65 + 65 = 6 × 65 = 390 miles correct answer is c ) 390 miles"
in a family 13 people eat only vegetarian , 7 people eat only non veg . , 8 people eat both veg and non veg . . how many people eat veg in the family ?
[ "20", "11", "9", "31", "21" ]
E
"total people eat veg = only veg + both veg and non veg total = 13 + 8 = 21 answer = e"
if p / q = 4 / 5 , then the value of 11 / 7 + { ( 2 q - p ) / ( 2 q + p ) } is ?
[ "3 / 7", "34", "1", "2", "3" ]
D
answer given exp . = 11 / 7 + { ( 2 q - p ) / ( 2 q + p ) } dividing numerator as well as denominator by q , exp = 11 / 7 + { 2 - p / q ) / ( 2 + p / q ) } = 11 / 7 + { ( 2 - 4 / 5 ) / ( 2 + 4 / 5 ) } = 11 / 7 + 6 / 14 = 11 / 7 + 3 / 7 = 14 / 7 = 2 correct option : d
if x ^ 2 + y ^ 2 = 13 and xy = 3 , then ( x − y ) ^ 2 =
[ "7", "11", "14", "17", "20" ]
A
"but you can not take xy + 3 to mean xy = - 3 . . only if xy + 3 = 0 , it will mean xy = - 3 . . rest your solution is perfect and you will get your correct answer as 13 - 2 * 3 = 7 . . answer a"
a big container is 40 % full with water . if 14 liters of water is added , the container becomes 3 / 4 full . what is the capacity of the big container in liters ?
[ "32", "36", "40", "44", "48" ]
C
14 liters is 35 % of the capacity c . 14 = 0.35 c c = 14 / 0.35 = 40 liters . the answer is c .
the ratio of the arithmetic mean of two numbers to one of the numbers is 5 : 8 . what is the ratio of the smaller number to the larger number ?
[ "1 : 8", "1 : 6", "1 : 5", "1 : 4", "1 : 3" ]
D
"for two numbers , the arithmetic mean is the middle of the two numbers . the ratio of the mean to the larger number is 5 : 8 , thus the smaller number must have a ratio of 2 . the ratio of the smaller number to the larger number is 2 : 8 = 1 : 4 . the answer is d ."
the salaries of a , b , and c are in the ratio of 1 : 2 : 3 . the salary of b and c together is rs . 6000 . by what percent is the salary of c more than that of a ?
[ "209 %", "200 %", "290 %", "600 %", "100 %" ]
B
explanation : let the salaries of a , b , c be x , 2 x and 3 x respectively . then , 2 x + 3 x = 6000 = > x = 1200 . a ' s salary = rs . 1200 , b ' s salary = rs . 2400 , and cs salary rs . 3600 . excess of c ' s salary over a ' s = [ ( 2400 / 1200 ) x 100 ] = 200 % . answer : b ) 200 %
a man swims downstream 96 km and upstream 40 km taking 8 hours each time ; what is the speed of the current ?
[ "3.5 kmph", "1.5 kmph", "13 kmph", "6.5 kmph", "7 : 3 kmph" ]
A
"explanation : 96 - - - 8 ds = 12 ? - - - - 1 40 - - - - 8 us = 5 ? - - - - 1 s = ? s = ( 12 - 5 ) / 2 = 3.5 answer : option a"
vinoth can complete a painting work in 20 days . prakash can do the same work in 25 days . they start the work together but vinoth quit after 3 days of work . how many days are required to complete the remaining painting work by prakash .
[ "15.25 days", "16.25 days", "17.25 days", "18.25 days", "19.25 days" ]
D
vinoth can complete the painting work in one day is 1 / 20 prakash can complete the same work in one day is 1 / 25 both of them can complete the work in 1 / 20 + days = 9 / 100 ( 1 / 20 + 1 / 25 ) they must have completed in three days = 9 / 100 * 3 = 27 / 100 remaining work to be done is by prakash = 1 - 27 / 100 = 73 / 100 for one work , prakash can do in 25 days for 73 / 100 work , he can do in 73 / 100 * 25 = 73 / 4 days or 18.25 days answer : d
the total cost of a vacation was divided among 3 people . if the total cost of the vacation had been divided equally among 5 people , the cost per person would have been $ 50 less . what was the total cost cost of the vacation ?
[ "$ 200", "$ 375", "$ 400", "$ 500", "$ 600" ]
B
c for cost . p price per person . c = 3 * p c = 5 * p - 250 substituting the value of p from the first equation onto the second we get p = 125 . plugging in the value of p in the first equation , we get c = 375 . which leads us to answer choice b
how many ounces of a 60 % salt solution must be added to 30 ounces of a 20 percent salt solution so that the resulting mixture is 40 % salt ?
[ "16.67", "30", "50", "60.33", "70" ]
B
"let x = ounces of 60 % salt solution to be added . 2 * 30 + . 6 x = . 4 ( 30 + x ) x = 30 answer b"
if 20 % of a is the same as 30 % of b , then a : b is :
[ "5 : 4", "5 : 3", "4 : 3", "3 : 2", "1 : 3" ]
D
"expl : 20 % of a i = 30 % of b = 20 a / 100 = 30 b / 100 = 3 / 2 = 3 : 2 answer : d"
d and e are two points respectively on sides ab and ac of triangle abc such that de is parallel to bc . if the ratio of area of triangle ade to that of the trapezium decb is 144 : 25 and bc = 13 cm , then find the length of de .
[ "12", "13", "14", "11", "15" ]
C
"abc and ade are similar triangles . so ( side of abc / side of ade ) ^ 2 = 25 / 169 side of abc / side of ade = 5 / 13 so the length of de = 5 answer - c"
working alone at its constant rate , machine a produces x boxes in 10 minutes and working alone at its constant rate , machine b produces 2 x boxes in 5 minutes . how many minutes does it take machines a and b , working simultaneously at their respective constant rates , to produce 10 x boxes ?
[ "13 minutes", "14 minutes", "15 minutes", "16 minutes", "20 minutes" ]
E
"rate = work / time given rate of machine a = x / 10 min machine b produces 2 x boxes in 5 min hence , machine b produces 4 x boxes in 10 min . rate of machine b = 4 x / 10 we need tofind the combined time that machines a and b , working simultaneouslytakeat their respective constant rates let ' s first find the combined rate of machine a and b rate of machine a = x / 10 min + rate of machine b = 4 x / 10 = 5 x / 10 now combine time = combine work needs to be done / combine rate = 10 x / 5 x * 10 = 6 min ans : e"
if y > 0 , ( 1 y ) / 20 + ( 3 y ) / 10 is what percent of y ?
[ "35 %", "50 %", "60 %", "70 %", "80 %" ]
A
"can be reduced to y / 20 + 3 y / 10 = 7 y / 20 = 35 % a"
how many of the positive factors of 25 , 15 and how many common factors are there in numbers ?
[ "1", "2", "3", "4", "5" ]
B
"factors of 25 - 1 , 5 , and 25 factors of 15 - 1 , 3 , 5 and 15 comparing both , we have three common factors of 45,16 - 2 answer b"
a certain college ' s enrollment at the beginning of 1992 was 20 percent greater than it was at the beginning of 1991 , and its enrollment at the beginning of 1993 was 5 percent greater than it was at the beginning of 1992 . the college ' s enrollment at the beginning of 1993 was what percent greater than its enrollment at the beginning of 1991 ?
[ "17.5 %", "26 %", "30 %", "35 %", "38 %" ]
B
"suppose enrollment in 1991 was 100 then enrollment in 1992 will be 120 and enrollment in 1993 will be 120 * 1.05 = 126 increase in 1993 from 1991 = 126 - 100 = 26 answer : b"
of the 17,210 employees of the anvil factory , 2 / 7 are journeymen . if half of the journeymen were laid off , what percentage of the total remaining employees would be journeymen ?
[ "14.3 %", "16.67 %", "33 %", "28.6 %", "49.67 %" ]
D
"the exam gives us a number that is easily divisible by 7 to pique our curiosity and tempt us into calculating actual numbers ( also because otherwise the ratio would be incorrect ) . since the question is about percentages , the actual numbers will be meaningless , as only the ratio of that number versus others will be meaningful . nonetheless , for those who are curious , each 1 / 7 portion represents ( 14210 / 7 ) 2,030 employees . this in turn means that 4,060 employees are journeymen and the remaining 10,150 are full time workers . if half the journeymen were laid off , that would mean 1 / 7 of the total current workforce would be removed . this statistic is what leads many students to think that since half the journeymen are left , the remaining journeymen would represent half of what they used to be , which means 1 / 7 of the total workforce . if 1 / 7 of the workforce is journeymen , and 1 / 7 is roughly 14.3 % , then answer choice a should be the right answer . in this case , though , it is merely the tempting trap answer choice . what changed between the initial statement and the final tally ? well , you let go of 1 / 7 of the workforce , so the total number of workers went down . the remaining workers are still 1 / 7 of the initial workers , but the group has changed . the new workforce is smaller than the original group , specifically 6 / 7 of it because 1 / 7 was eliminated . the remaining workers now account for 1 / 7 out of 6 / 7 of the force , which if we multiply by 7 gives us 1 out of 6 . this number as a percentage is answer choice b , 28.6 % . using the absolute numbers we calculated before , there were 4,060 journeymen employees out of 14,210 total . if 2,030 of them are laid off , then there are 2,030 journeyman employees left , but now out of a total of ( 14,210 - 2,030 ) 12,180 employees . 2,030 / 12,180 is exactly 1 / 6 , or 16.67 % . the answer will work with either percentages or absolute numbers , but the percentage calculation will be significantly faster and applicable to any similar situation . the underlying principle of percentages ( and , on a related note , ratios ) can be summed up in the brainteaser i like to ask my students : if you ’ re running a race and you overtake the 2 nd place runner just before the end , what position do you end up in ? the correct answer is 2 nd place . percentages , like ratios and other concepts of relative math , depend entirely on the context . whether 100 % more of something is better than 50 % more of something else depends on the context much more than the percentages quoted . when it comes to percentages on the gmat , the goal is to understand them enough to instinctively not fall into the traps laid out for you . d"
an electric pump can fill a tank in 10 hours . because of a leak in the tank , it took 20 hours to fill the tank . if the tank is full , how much time will the leak take to empty it ?
[ "10 hours", "12 hours", "20 hours", "5 hours", "15 hours" ]
C
"work done by the leak in 1 hour = 1 / 10 - 1 / 20 = 1 / 20 the leak will empty the tank in 20 hours answer is c"
for every even positive integer m , f ( m ) represents the product of all even integers from 2 to m , inclusive . for example , f ( 12 ) = 2 x 4 x 6 x 8 x 10 x 12 . what is the greatest prime factor of f ( 36 ) ?
[ "2", "5", "11", "17", "23" ]
D
"f ( 36 ) = 2 * 4 * 6 * 8 * 10 * 12 * 14 * 16 * 18 * 20 * 22 * 24 * 26 * 28 * 30 * 32 * 34 * 36 the greatest prime factor in this list is 17 . the answer is d ."
pipe a can fill a tank in 10 hours . due to a leak at the bottom , it takes 15 hours for the pipe a to fill the tank . in what time can the leak alone empty the full tank ?
[ "76", "84", "56", "75", "30" ]
E
let the leak can empty the full tank in x hours 1 / 10 - 1 / x = 1 / 15 = > 1 / x = 1 / 10 - 1 / 15 = ( 3 - 2 ) / 30 = 1 / 30 = > x = 30 . answer : e
5 women can do a work in two days . 10 men can complete the same work in five days . what is the ratio between the capacity of a man and a woman ?
[ "1 : 2", "1 : 5", "2 : 3", "3 : 2", "none of these" ]
B
"explanation : ( 5 ã — 2 ) women can complete the work in 1 day . â ˆ ´ 1 woman ' s 1 day ' s work = 1 / 10 ( 10 ã — 5 ) men can complete the work in 1 day . â ˆ ´ 1 man ' s 1 day ' s work = 1 / 50 so , required ratio = 1 / 10 : 1 / 50 = 1 : 5 answer : b"
what is the positive difference between the sum of the squares of the first 8 positive integers and the sum of the prime numbers between the first square and fourth square ?
[ "161", "162", "163", "164", "165" ]
C
"forget conventional ways of solving math questions . in ps , ivy approach is the easiest and quickest way to find the answer . the sum of the squares of the first 4 positive integers = 1 ^ 2 + 2 ^ 2 + 3 ^ 2 + . . . + 8 ^ 2 = 204 the sum of the prime numbers between the first square ( = 1 ) and fourth square ( = 16 ) = 2 + 3 + 5 + 7 + 11 + 13 = 41 . so the difference between 41 and 204 is 163 . so the answer is ( c ) ."
the average age of 19 persons in a office is 15 years . out of these , the average age of 5 of them is 14 years and that of the other 9 persons is 16 years . the age of the 15 th person is ?
[ "9", "71", "85", "92", "90" ]
B
"age of the 15 th student = 19 * 15 - ( 14 * 5 + 16 * 9 ) = 285 - 214 = 71 years answer is b"
a pet store regularly sells pet food at a discount of 10 percent to 30 percent from the manufacturer ’ s suggested retail price . if during a sale , the store discounts an additional 20 percent from the discount price , what would be the lowest possible price of a container of pet food that had a manufacturer ’ s suggested retail price o f $ 40.00 ?
[ "$ 10.00", "$ 11.20", "$ 22.40", "$ 16.00", "$ 18.00" ]
C
"for retail price = $ 40 first maximum discounted price = 40 - 30 % of 40 = 40 - 12 = 28 price after additional discount of 20 % = 28 - 20 % of 28 = 28 - 5.6 = 22.4 answer : option c"
the perimeter of an equilateral triangle is 60 . if one of the sides of the equilateral triangle is the side of an isosceles triangle of perimeter 45 , then how long is the base of isosceles triangle ?
[ "5 units", "10 units", "15 units", "20 units", "25 units" ]
A
"the base of the isosceles triangle is 45 - 20 - 20 = 5 units the answer is a ."
a small table has a length of 12 inches and a breadth of b inches . cubes are placed on the surface of the table so as to cover the entire surface . the maximum side of such cubes is found to be 4 inches . also , a few such tables are arranged to form a square . the minimum length of side possible for such a square is 80 inches . find b .
[ "8', '", "16', '", "24', '", "32', '", "48']" ]
B
from the info that the maximum sides of the cubes is 4 , we know that the gcf of 12 ( = 2 ^ 2 * 3 ) andbis 4 ( = 2 ^ 2 ) , sob = 2 ^ x , where x > = 2 . from the second premise , we know that the lcm of 12 ( 2 ^ 2 * 3 ) andbis 80 ( 2 ^ 4 * 5 ) , sob = 2 ^ 4 or 2 ^ 4 * 5 ( 16 or 80 ) . combining 2 premises shows the answer is b ( 16 ) .
calculate the ratio between x and y if 25 % of x equal to 40 % of y ?
[ "5 : 8", "5 : 9", "5 : 7", "5 : 6", "5 : 4" ]
A
"explanation : 25 x = 40 y x : y = 25 : 40 = 5 : 8 answer : a"
. 003 / ? = . 01
[ ". 3", ". 09", ". 009", ". 0009", "none of them" ]
A
"let . 003 / x = . 01 ; then x = . 003 / . 01 = . 3 / 1 = . 3 answer is a"
if √ 10 = 3.16 , find the value of if √ 5 / 2
[ "1.3", "1.58", "2.03", "2.15", "3.15" ]
B
explanation : √ ( 5 / 2 ) = √ ( 5 × 2 / 2 × 2 ) = √ ( 10 ) / 2 = 3.16 / 2 = 1.58 answer : b
the length of a rectangular plot is 20 metres more than its breadth . if the cost of fencing the plot @ rs . 26.50 per metre is rs . 7420 , what is the length of the plot in metres ?
[ "20", "200", "300", "400", "80" ]
E
"let length of plot = l meters , then breadth = l - 20 meters and perimeter = 2 [ l + l - 20 ] = [ 4 l - 40 ] meters [ 4 l - 40 ] * 26.50 = 7420 [ 4 l - 40 ] = 7420 / 26.50 = 280 4 l = 320 l = 320 / 4 = 80 meters . answer : e"
30 men can do a work in 40 days . when should 12 men leave the work so that the entire work is completed in 40 days after they leave the work ?
[ "18 days", "10 days", "55 days", "44 days", "22 days" ]
A
"total work to be done = 30 * 40 = 1200 let 12 men leave the work after ' p ' days , so that the remaining work is completed in 40 days after they leave the work . 40 p + ( 12 * 40 ) = 1200 40 p = 720 = > p = 18 days answer : a"
carrie likes to buy t - shirts at the local clothing store . they cost $ 9.65 each . one day , she bought 12 t - shirts . how much money did she spend ?
[ "$ 115.8", "$ 248.75", "$ 200", "$ 171.6", "$ 190" ]
A
$ 9.65 * 12 = $ 115.8 . answer is a .
a train 110 m long is running with a speed of 30 km / h . in how many seconds will the train pass a man who is running at 3 km / h in the direction opposite to that in which the train is going ?
[ "6", "8", "10", "12", "14" ]
D
"the speed of the train relative to the man = 30 + 3 = 33 km / h . 33000 m / h * 1 h / 3600 s = ( 330 / 36 ) m / s ( 110 m ) / ( 330 / 36 m / s ) = ( 110 * 36 ) / 330 = 36 / 3 = 12 seconds the answer is d ."
kanul spent $ 3000 in buying raw materials , $ 1000 in buying machinery and 30 % of the total amount he had as cash with him . what was the total amount ?
[ "$ 5825.16", "$ 5725.26", "$ 5714.28", "$ 5912.52", "$ 5614.46" ]
C
"let the total amount be x then , ( 100 - 30 ) % of x = 3000 + 1000 70 % of x = 4000 70 x / 100 = 4000 x = $ 40000 / 7 x = $ 5714.28 answer is c"
a sporting goods store sold 64 frisbees in one week , some for $ 3 and the rest for $ 4 each . if receipts from frisbee sales for the week totaled $ 204 , what is the fewest number of $ 3 frisbees that could have been sold ?
[ "24", "12", "8", "52", "2" ]
D
"in this question however , because we are told that exactly 64 frisbees have been sold and revenue was exactly $ 204 , there is only one possible solution for the number of $ 3 and $ 4 frisbees sold . to solve , we have 2 equations and 2 unknowns let x = number of $ 3 frisbees sold let y = number of $ 4 frisbees sold x + y = 64 3 x + 4 y = 204 x = 64 - y 3 ( 64 - y ) + 4 y = 204 192 - 3 y + 4 y = 204 y = 12 x = 64 - 12 = 52 d"
two trains 110 meters and 200 meters in length respectively are running in opposite directions , one at the rate of 80 km and the other at the rate of 65 kmph . in what time will they be completely clear of each other from the moment they meet ?
[ "4.85", "7.69", "6.85", "5.85", "6.15" ]
B
"t = ( 110 + 200 ) / ( 80 + 65 ) * 18 / 5 t = 7.69 answer : b"
how many 1 / 10 s are there in 37 1 / 2 ?
[ "375", "475", "500", "670", "700" ]
A
"required number = ( 75 / 2 ) / ( 1 / 10 ) = ( 75 / 2 x 10 / 1 ) = 375 . answer : a"
a circle graph shows how the megatech corporation allocates its research and development budget : 12 % microphotonics ; 24 % home electronics ; 15 % food additives ; 29 % genetically modified microorganisms ; 8 % industrial lubricants ; and the remainder for basic astrophysics . if the arc of each sector of the graph is proportional to the percentage of the budget it represents , how many degrees of the circle are used to represent basic astrophysics research ?
[ "43 °", "10 °", "18 °", "36 °", "52 °" ]
A
"here all percentage when summed we need to get 100 % . as per data 12 + 24 + 15 + 29 + 8 = 88 % . so remaining 12 % is the balance for the astrophysics . since this is a circle all percentage must be equal to 360 degrees . 100 % - - - - 360 degrees then 12 % will be 43 degrees . . imo option a ."
how much interest will $ 10,000 earn in 3 months at an annual rate of 6 % ?
[ "$ 250", "$ 150", "$ 450", "$ 550", "$ 650" ]
B
"soln : - 6 months = 1 / 4 of year ; 6 % = 6 / 100 = 3 / 50 ; $ 10,000 ( principal ) * 3 / 50 ( interest rate ) * 1 / 4 ( time ) = $ 150 . answer : b"
how many different values of positive integer x , for which | x + 9 | < x , are there ?
[ "0", "2", "3", "8", "16" ]
C
"answer c i opted to put the random value option . i used 0 , 9 , - 9 and the the extreme of 10 and - 10 . . i was able to solve it in 1 : 09 c"
if the average of 10 consecutive integers is 21.5 then the 10 th integer is : -
[ "15", "20", "23", "26", "25" ]
D
"the average falls between the 5 th and 6 th integers , integer 5 = 21 , integer 6 = 22 . counting up to the tenth integer we get 26 . answer : d"
in a box of 8 pens , a total of 3 are defective . if a customer buys 2 pens selected at random from the box , what is the probability that neither pen will be defective ?
[ "2 / 10", "3 / 11", "4 / 13", "5 / 14", "6 / 17" ]
D
"p ( neither pen is defective ) = 5 / 8 * 4 / 7 = 5 / 14 the answer is d ."
in filling a room with gas 100 m * 10 m * 10 m the volumes of gas will be ?
[ "100 cu . m', '", "1000 cu . m', '", "10000 cu . m', '", "100000 cu . m', '", "10000000 cu . m']" ]
C
100 * 10 * 10 = 10000 answer : c
a train passes a station platform in 30 sec and a man standing on the platform in 12 sec . if the speed of the train is 54 km / hr . what is the length of the platform ?
[ "227", "240", "200", "178", "270" ]
E
"speed = 54 * 5 / 18 = 15 m / sec . length of the train = 15 * 12 = 180 m . let the length of the platform be x m . then , ( x + 180 ) / 30 = 15 = > x = 270 m . answer : e"
a right triangle is inscribed in a circle . the legs of the triangle have lengths 6 and 8 . what is the diameter of the circle ?
[ "8', '", "8 π', '", "9 √ 3', '", "10', '", "12']" ]
D
property of a right triangle inscribed in a circle is that when an angle is made from diameter of the circle , it is a right triangle . or if a right triangle is made inscribed in a circle , its its longest side is the diameter of the circle . hence diameter = ( 6 ^ 2 + 8 ^ 2 ) ^ 1 / 2 = 10 d is the answer
what is 15 percent of 64 ?
[ "7.2", "8.4", "9.6", "10.4", "11.8" ]
C
"( 15 / 100 ) * 64 = 9.6 the answer is c ."
each week a restaurant serving mexican food uses the same volume of chili paste , which comes in either 55 - ounce cans or 15 - ounce cans of chili paste . if the restaurant must order 30 more of the smaller cans than the larger cans to fulfill its weekly needs , then how many larger cans are required to fulfill its weekly needs ?
[ "15", "28", "18", "24", "21" ]
A
"let x be the number of 55 ounce cans . therefore ( x + 30 ) is the number of 15 ounce cans . total volume is same , therefore 55 x = 15 ( x + 30 ) 30 x = 450 x = 15 ans - a"
for any positive integer n , the sum of the first n positive integers equals n ( n + 1 ) / 2 . what is the sum of all the even integers between 99 and 181 ?
[ "3820", "5740", "6580", "7360", "9200" ]
B
"100 + 102 + . . . + 180 = 100 * 41 + ( 2 + 4 + . . . + 80 ) = 100 * 41 + 2 * ( 1 + 2 + . . . + 40 ) = 100 * 41 + 2 ( 40 ) ( 41 ) / 2 = 100 * 41 + 40 * 41 = 140 ( 41 ) = 5740 the answer is b ."
a salesman â € ™ s terms were changed from a flat commission of 5 % on all his sales to a fixed salary of rs . 1000 plus 2.5 % commission on all sales exceeding rs . 4,000 . if his remuneration as per new scheme was rs . 800 more than that by the previous schema , his sales were worth ?
[ "s . 4,000", "s . 12,000", "s . 30,000", "s . 40,000", "s . 50,000" ]
A
"[ 1000 + ( x - 4000 ) * ( 2.5 / 100 ) ] - x * ( 5 / 100 ) = 800 x = 4000 answer : a"
if k is an integer and 0.0010101 x 10 ^ k is greater than 10 , what is the least possible value of k ?
[ "2", "3", "4", "5", "6" ]
C
"0.0010101 * 10 ^ k > 10 we need to move the decimal point to the right 4 places to get 10.101 this is equivalent to multiplying by 10 ^ 4 . the answer is c ."
if a and b are positive integers and ( 3 ^ a ) ^ b = 3 ^ 3 , what is the value of 3 ^ a * 3 ^ b ?
[ "3", "9", "81", "27", "243" ]
C
3 ^ ab = 3 ^ 3 therefore ab = 3 either a = 1 or 3 or b = 3 or 1 therefore 3 ^ a * 3 ^ b = 3 ^ ( a + b ) = 3 ^ 4 = 81 c
a gardener is going to plant 2 red rosebushes and 2 white rosebushes . if the gardener is to select each of the bushes at random , one at a time , and plant them in a row , what is the probability that the 2 rosebushes in the middle of the row will be the red rosebushes ?
[ "1 / 12", "1 / 6", "1 / 5", "1 / 3", "½" ]
B
we are asked to find the probability of one particular pattern : wrrw . total # of ways a gardener can plant these four bushes is the # of permutations of 4 letters wwrr , out of which 2 w ' s and 2 r ' s are identical , so 4 ! / 2 ! 2 ! = 6 ; so p = 1 / 6 answer : b .
a certain university will select 1 of 5 candidates eligible to fill a position in the mathematics department and 2 of 8 candidates eligible to fill 2 identical positions in the computer science department . if none of the candidates is eligible for a position in both departments , how many different sets of 3 candidates are there to fill the 3 positions ?
[ "138", "140", "142", "145", "148" ]
B
"1 c 5 * 2 c 8 = 5 * 28 = 140 the answer is ( b )"
what will be the lcm of 8 , 24 , 36 and 54
[ "54", "108", "216", "432", "none of these" ]
C
explanation : lcm of 8 - 24 - 36 - 54 will be 2 * 2 * 2 * 3 * 3 * 3 = 216 answer : option c
a number exceeds by 35 from its 3 / 8 part . then the number is ?
[ "56", "35", "39", "40", "45" ]
A
"x – 3 / 8 x = 35 x = 56 answer : a"
if 0.75 : x : : 5 : 6 , then x is equal to :
[ "1.12", "1.16", "1.2", "0.9", "none of these" ]
D
"explanation : ( x * 5 ) = ( 0.75 * 6 ) x = 4.5 / 5 = 0.9 answer : d"
two trains of equal lengths take 10 sec and 14 sec respectively to cross a telegraph post . if the length of each train be 120 m , in what time will they cross other travelling in opposite direction ?
[ "10", "12", "13", "11.7", "15" ]
D
"speed of the first train = 120 / 10 = 12 m / sec . speed of the second train = 120 / 14 = 8.6 m / sec . relative speed = 12 + 8.6 = 20.6 m / sec . required time = ( 120 + 120 ) / 20.6 = 11.7 sec . answer : option d"
four equal circles are described about the four corners of a square so that each touches two of the others . if a side of the square is 14 cm , then the area enclosed between the circumferences of the circles is :
[ "24 cm 2', '", "42 cm 2', '", "154 cm 2', '", "196 cm 2', '", "none of these']" ]
B
the shaded area gives the required region . area of the shaded region = area of the square – area of four quadrants of the circles = ( 14 ) 2 - 4 × 1 ⁄ 4 π ( 7 ) 2 = 196 - 22 ⁄ 7 × 49 = 196 - 154 = 42 cm 2 answer b
in the coordinate plane , line a has a slope of - 1 and an x - intercept of 1 . line b has a slope of 4 and a y - intercept of - 4 . if the two lines intersect at the point ( a , b ) , what is the sum a + b ?
[ "0", "1", "2", "3", "4" ]
B
"the equation of line a is y = - x + 1 the equation of line b is y = 4 x - 4 4 x - 4 = - x + 1 x = 1 y = 0 the point of intersection is ( 1,0 ) and then a + b = 1 . the answer is b ."
if the annual increase in the population of a town is 10 % and the present number of people is 10000 , what will the population be in 2 years ?
[ "12100", "15240", "12456", "11452", "10002" ]
A
"the required population is = 10000 ( 1 + 10 / 100 ) ^ 2 = 10000 * 11 / 10 * 11 / 10 = 12100 answer is a"
the sum of two consecutive integers is 41 . find the numbers .
[ "17 , 18", "7 , 8", "5 , 6", "20,21", "8 , 9" ]
D
"n + ( n + 1 ) = 41 2 n + 1 = 41 2 n = 40 n = 20 answer : d"
calculate the circumference of a circular field whose radius is 10 centimeters .
[ "20 π cm", "19 π cm", "28 π cm", "25 π cm", "30 π cm" ]
A
"circumference c is given by c = 2 π r = 2 π * 10 = 20 π cm answer : a"
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