Rationale: Divisibility rule of 6: Number must be divisible by both 2 and 3
Option A: 10032, Divisible by 2. Hence divisible by 6
Option B: 21192, Divisible by 2 & 3. Hence divisible by 6
Option C: 47816, Divisible by 2. Hence divisible by 6
Option D: 91232, Divisible by 2. Hence divisible by 6
Option E: 72031, Not divisible by 2 or 3. Hence 72031 is not divisible by 6
The answer: (E)
Question: Which of the following is not divisible by 6?
Options:
(A) 10032
(B) 21192
(C) 47816
(D) 91232
(E) 72031
Reasoning: Part filled by (A + B + C) in 3 minutes = 3(1/30 + 1/20 + 1/10) = 11/20
Part filled by C in 3 minutes = 3/10
Required ratio = 3/10 * 20/11 = 6/11
Ans: (B)
Question: Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?
Options:
(A) 6/15
(B) 6/11
(C) 6/14
(D) 6/12
(E) 6/13
Rationale: P = (P*30*R)/100
R = 3 1/3%
The answer: (A)
Question: At what rate percent on simple interest will a sum of money double itself in 30 years?
Options:
(A) 3 1/3%
(B) 3 5/3%
(C) 3 1/9%
(D) 3 1/5%
(E) 3 1/7%
Reasoning: Work done by X in 1 day = 1/21
Work done by Y in 1 day = 1/15
Work done by Y in 10 days = 10/15 = 2/3
Remaining work = 1 2/3 = 1/3
Number of days in which X can finish the remaining work = (1/3) / (1/21) = 7
Ans: (C)
Question: X can finish a work in 21 days. Y can finish the same work in 15 days. Yworked for 10 days and left the job. how many days does X alone need to finish the remaining work?
Options:
(A) 3
(B) 5
(C) 7
(D) 8
(E) 9
Rationale: A + B = 1/20 + 1/15 = 7/60
A + C = 1/20 + 1/12 = 8/60
7/60 + 8/60 = 15/60 = 1/4
4 days * 2 = 8 days
The answer: (B)
Question: A can do a piece of work in 20 days. B in 15 days A and C in 12 days. In how many days can A finish the work if he is assisted by B on one day and C on the next, alternately?
Options:
(A) 7 days
(B) 8 days
(C) 3 days
(D) 9 days
(E) 2 days
Rationale: T = 192/32 = 6 h
T = 6 - 3 = 3
Time Ratio = 6:3 = 2:1
Speed Ratio = 1:2
The answer: (A)
Question: A motorcyclist goes from Bombay to Pune, a distance of 192 kms at an average of 32 kmph speed. Another man starts from Bombay by car 2 hours after the first, and reaches Pune hour earlier. What is the ratio of the speed of the motorcycle and the car?
Options:
(A) 1:2
(B) 1:8
(C) 1:1
(D) 1:6
(E) 1:3