# Model Aptitude questions and answers for placement - Set 8

1)   Ramesh can complete a work in 12 days, working 7 hours a day. Suresh can complete the same work in 8 days, working 9 hours a day. If Ramesh and Suresh work together working 7 hours a day, in how many days can they complete the work?

a. 7 * 3 / 23
b. 5 * 7 / 13
c. 6 * 5 / 13
d. 6 * 6 / 11
e. None of these
 Answer  Explanation ANSWER: 5 * 7 / 13 Explanation: Ramesh can finish the work in 12 * 7 = 84 hoursAmount of work he can complete in 1 hour = 1/84Suresh can finish the same work in 8 * 9 = 72 hoursAmount of work he can complete in 1 hour = 1/72 hoursWork done by both of them in 1 hour == 1/84 + 1/72 = 13/504Ramesh and Suresh together can complete the work in 504/13 hours.i.e. 504/13 * 1/7 = 72/13 daysi.e. 5 * 7 / 13 days

2)   If 500 gm of salt solution has 30% salt in it, how much salt must be added to make the concentration of salt 50% in the solution?

a. 200 gm
b. 100 gm
c. 90 gm
d. 50 gm
e. None of these
 Answer  Explanation ANSWER: 200 gm Explanation: Amount of water in solution = 100 % - 30 % = 70 % of totalAmount of water = 70 % x 500 = 350 gmAmount of water remains same for both the solutions. Therefore, let amount of new solution be x gm.x = 350 x (100/ 50)x = 700 Salt added = (700 – 500) = 200 gm Alternate solution:Quantity of sugar to be added := [Solution (Required % value – Present % value)] / (100 – Required % value)= [500 (50 – 30)] / 100 – 50= (500 x 20) / 50= 200 gm

3)   The L.C.M. Of 2, 2.7 and 0.09 is:

a. 5.4
b. 0.54
c. 0.054
d. 54
 Answer  Explanation ANSWER: 54 Explanation: Given numbers are 2.00, 2.70 and 0.09.L.C.M. of 200, 270 and 9 is 5400.L.C.M. Of given numbers = 54.00 = 54

4)   Which of the following fraction is greater than 2/3 and less than 4/5 ?

a. 1/2
b. 9/10
c. 3/4
d. 5/6
 Answer  Explanation ANSWER: 3/4 Explanation: 1/2 = 0.5, 2/3 = 0.66, 4/5 = 0.8, 9/10 = 0.9, 3/4 = 0.75, 5/6 = 0.833,Clearly, 0.8 lies between 0.75 and 0.8333/4 lies between 2/3 and 4/5

5)   3/8 of 168 * 15 / 5 + X = 549 / 9 + 275

a. 107
b. 147
c. 10
d. 296
e. None of these
 Answer  Explanation ANSWER: 147 Explanation: Let 3/8 of 168 * 15 / 5 + X = 549 / 9 + 275Then, 63 * 15 / 5 + X = 61 + 27563 * 3 + X = 336189 + X = 336 X = 147

6)   The average of five consecutive odd numbers is 51. What is the difference between the highest and lowest number?

a. 3
b. 7
c. 8
d. 11
e. None of these
 Answer  Explanation ANSWER: 8 Explanation: Let the numbers be x, x + 2, x + 4, x + 6 and x + 8.Then, [x + (x + 2) + (x + 4) + (x + 6) + (x + 8)] / 5 = 515x + 20 = 255x = 47So, required difference = (47 + 8) – 47 = 8

7)   If the sum of a number and its square is 272, What is the number?

a. 14
b. 16
c. 19
d. 21
e. None of these
 Answer  Explanation ANSWER: 16 Explanation: Let the integer be x.Then, x + x2 = 272x2 + x - 272 = 0(x + 17) (x – 16) = 0x = 16

8)   The present ages of three persons are in proportions 4 : 7 : 9. Eight years ago, the sum of their ages was 76. Find their present ages (in years).

a. 8, 20, 28
b. 12, 21, 27
c. 20, 35, 45
d. None of these
 Answer  Explanation ANSWER: 20, 35, 45 Explanation: Let their present ages be 4x, 7x and 9x years respectively.Then, (4x – 8) + (7x – 8) + (9x – 8) = 7620x = 100x = 5Their present ages are 20 years, 35 years and 45 years respectively.

9)   If 5a = 625, then the value of 5(a – 2) is:

a. 5
b. 25
c. 125
d. 625
 Answer  Explanation ANSWER: 25 Explanation: 5a = 625 5a = 54 a = 4Therefore,5(a – 2) = 5(4 – 2) = 52 = 25

10)   The number which exceeds 12% of it by 52.8 is:

a. 50
b. 52
c. 58
d. 60
 Answer  Explanation ANSWER: 60 Explanation: Let the number be x. Then, x – 12% of x = 52.8x – (12/100)x = 52.8x (1– 12/100) = 52.8(88/100)x = 52.8x = (100 X 52.8) / 88 = 60