q: The edge of a cube is 5a cm. Find its surface?
Options:
(A) 24a8
(B) 150a2
(C) 24a1
(D) 24a2
(E) 24a7
a: Stream of consciousness: 6a2 = 6 * 5a * 5a = 150a2 The answer is (B).

question: What is the greatest positive integer x such that 4^x is a factor of 64^10?
Options:
(A) 5
(B) 9
(C) 10
(D) 20
(E) 30
answer: Stream of consciousness: 64^10 = (4^3)^10 = 4^30 The answer is (E).

q: The balance of a trader weighs 10% less than it should. Still the trader marks up his goods to get an overall profit of 20%. What is the mark up on the cost price?
Options:
(A) 40%
(B) 8%
(C) 25%
(D) 16.66%
(E) 9%
a: Stream of consciousness: Original cost before weight adjustment: X
Cost after 90% weight adjustment: 9/10 X
20% profit on 9/10X: (120/100)(9/10)(X) or 108X/100
Mark up on original cost of X: (108X/100)/X-1 = 8/100 The answer is (B).

question: At 15:00 there were 20 students in the computer lab. At 15:03 and every three minutes after that, 3 students entered the lab. If at 15:10 and every ten minutes after that 7 students left the lab, how many students were in the computer lab at 15:44 ?
Options:
(A) 7
(B) 14
(C) 25
(D) 27
(E) 30
answer: Stream of consciousness: Initial no of students + 3 * (1 + No of possible 3 minute intervals between 15:03 and 15:44) -
8 *(1 + No of possible 10 minute intervals between 15:10 and 15:44)
20 + 3*14 -8 * 4 = 25 The answer is (C).

q: Which of the following is a prime number ?
Options:
(A) 90
(B) 94
(C) 96
(D) 97
(E) 98
a: Stream of consciousness: Clearly, 97 is a prime number. The answer is (D).

q: A and B together can complete a work in 12 days. A alone can complete it in 20 days. If B does the work only for half a day daily, then in how many days A and B together will complete the work?
Options:
(A) 65 days
(B) 85 days
(C) 15 days
(D) 45 days
(E) 13 days
a:
Stream of consciousness: B's 1 day work = (1/12 - 1/20) = 1/30
Now, (A + B)'s 1 day work = (1/20 + 1/60) = 1/15
So, A and B together will complete the work in 15 days. The answer is (C).