q: There are 9 fictions and 6 non-fictions. How many cases are there such that 2 fictions and 2 non-fictions are selected from them?
Options:
(A) 90
(B) 120
(C) 540
(D) 180
(E) 200
a: OK... Number of ways of selecting 2 fiction books = 9C2
Number of ways of selecting 2 non fiction books = 6C2
9C2 * 6C2 = 36 * 15 = 540
The answer is (C).

q: How many seconds will a train 120 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph?
Options:
(A) 17 sec
(B) 21 sec
(C) 25 sec
(D) 27 sec
(E) 29 sec
a: OK... D = 120 + 150 = 270
S = 36 * 5/18 = 10 mps
T = 270/10 = 27 sec
The answer is (D).

q: Anil can do a work in 15 days while Sunil can do it in 25 days. How long will they take if both work together?
Options:
(A) 3 4/9 days
(B) 8 4/9 days
(C) 9 3/8 days
(D) 6 3/8 days
(E) none of these
a:
OK... 1/15 + 1/25 = 8/75
75/8 = 9 3/8 days
The answer is (C).