question: A can do a job in 18 days and B can do it in 30 days. A and B working together will finish twice the amount of work in ------- days?
Options:
(A) 22 1/8 days
(B) 22 1/2 days
(C) 22 6/2 days
(D) 72 1/2 days
(E) 23 1/2 days
answer: Stream of consciousness: 1/18 + 1/30 = 8/90 = 4/45
45/4 = 11 1/4 *2 = 22 1/2 days The answer is (B).

q: The compound ratio of 2/3, 6/7, 4/3 and 1/8 is given by?
Options:
(A) 2/21
(B) 1/48
(C) 1/98
(D) 1/96
(E) 1/68
a: Stream of consciousness: 2/3 * 6/7 * 4/3 * 1/8 = 48/504 = 2/21 The answer is (A).

question: The average of 13 result is 20. Average of the first 8 of them is 20 and that of the last 8 is 40. Find the 8th result?
Options:
(A) 35
(B) 37
(C) 46
(D) 90
(E) 100
answer: Stream of consciousness: Sum of all the 13 results = 13 * 20 = 260
Sum of the first 7 of them = 8 * 20 = 160
Sum of the last 7 of them = 8 * 40 = 320
So, the 8th number = 260 + 160 - 320 = 100. The answer is (E).

q: How much time will it take for an amount of 1000 to yield 100 as interest at 5% per annum of simple interest?
Options:
(A) 3 years
(B) 4 years
(C) 2 years
(D) 5 years
(E) 7 years
a: Stream of consciousness: Time = (100 x 100)/(1000 x 5) years = 2 years. The answer is (C).

question: The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?
Options:
(A) 17
(B) 16
(C) 17
(D) 19
(E) 62
answer: Stream of consciousness: Average of 20 numbers = 0
Sum of 20 numbers = (0 * 20) = 0
It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (-a). The answer is (D).

question: A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Options:
(A) 40
(B) 37
(C) 32
(D) 39
(E) 28
answer:
Stream of consciousness: Speed = 45 * 5/18 = 25/2 m/sec
Total distance covered = 360 + 140 = 500 m
Required time = 500 * 2/25 = 40 sec The answer is (A).