q: There are 8 books in a shelf that consist of 1 paperback books and 7 hardback books. If 3 books are selected at random without replacement, how many different combinations are there that at least one paperback book is selected?
Options:
(A) 21
(B) 45
(C) 50
(D) 55
(E) 60
a: Stream of consciousness: 8C3 [Select any four] - 7C3 [Select all hard backs] = 21 The answer is (A).

question: A can do a piece of work in 12 days. When he had worked for 2 days B joins him. If the complete work was finished in 8 days. In how many days B alone can finish the work?
Options:
(A) 18
(B) 77
(C) 66
(D) 55
(E) 12
answer: Stream of consciousness: 8/12 + 6/x = 1
X = 18 days The answer is (A).

q: Twenty coins are tossed simultaneously. In how many of the outcomes will the third coin turn up a head?
Options:
(A) 2^19
(B) 2^10
(C) 3 * 2^8
(D) 3 * 2^9
(E) 3 * 2^10
a: Stream of consciousness: Fix the third coin as H. The remaining 19 coins have 2^19 outcomes. The answer is (A).

question: The smallest prime number is:
Options:
(A) 1
(B) 2
(C) 3
(D) 4
(E) 5
answer: Stream of consciousness: The smallest prime number is 2. The answer is (B).

q: A train of 24 carriages, each of 60 meters length, when an engine also of 60 meters length is running at a speed of 60 kmph. In what time will the train cross a bridge 1.2 km long?
Options:
(A) 2 mins 14 sec
(B) 2 mins 34 sec
(C) 162 sec
(D) 244 sec
(E) 2 mins 44 sec
a: Stream of consciousness: D = 25 * 60 + 1200 = 2700 m
T = 2700/60 * 18/5 = 162 se The answer is (C).

q: What approximate value should come in place of question mark (?) in the following equation
287.532 + 1894.029 657.48 = 543.095 + ?
Options:
(A) 870
(B) 790
(C) 980
(D) 770
(E) 890
a:
Stream of consciousness: ? = 285 + 1895 655 545 or, ? = 980 The answer is (C).