q: In 100 m race, A covers the distance in 36 seconds and B in 45 seconds. In this race A beats B by:
Options:
(A) 10
(B) 12
(C) 30
(D) 40
(E) 20
a: OK... Dist = (100/45*9) = 20 m
The answer is (E).

q: P and Q invested in a shop. The profits were divided in the ratio of 2 : 3 respectively. If P invested Rs. 40,000, the amount invested by Q is:
Options:
(A) 35000
(B) 40000
(C) 50000
(D) 60000
(E) None
a: OK... Suppose Q invested Rs. y. Then, 40000/y = 2/3 or y = [40000 x 3 / 2] = 60000.
The answer is (D).

q: Two pipes A and B can fill a cistern in 8 and 12 minutes respectively, and a third pipe C can empty it in 15 minutes. How long will it take to fill the cistern if all the three are opened at the same time?
Options:
(A) 17 1/17 min
(B) 28 1/7 min
(C) 17 1/7 min
(D) 17 1/8 min
(E) 17 5/7 min
a:
OK... 1/8 + 1/12 - 1/15 = 17/120
120/17 = 7 1/17
The answer is (A).