Q: The H.C.F. of two numbers is 12 and their L.C.M. is 520. If one of the numbers is 480, then the other is:
Options:
(A) 13
(B) 18
(C) 21
(D) 24
(E) 38
A: OK... Stream of consciousness: Other number = (12 x 520)/480 = 13.
The answer is (A).

Q: A motorcyclist goes from Bombay to Pune, a distance of 128 kms at an average of 32 kmph speed. Another man starts from Bombay by car 2 hours after the first, and reaches Pune hour earlier. What is the ratio of the speed of the motorcycle and the car?
Options:
(A) 1:3
(B) 1:5
(C) 1:4
(D) 1:1
(E) 1:8
A: OK... Stream of consciousness: T = 128/32 = 4 h
T = 4 - 3 = 1
Time Ratio = 4:1 = 4:1
Speed Ratio = 1:4
The answer is (C).

Q: A, B, C together started a business. A invested Rs.6000 for 5 months B invested Rs.3600 for 6 months and C Rs.7500 for 3 months. If they get a total profit of Rs.7410. Find the share of A?
Options:
(A) 9179
(B) 3000
(C) 2997
(D) 2678
(E) 2682
A: OK... Stream of consciousness: 60*5:36*6:75*3
100: 72: 75
100/247 * 7410 = 3000
The answer is (B).

Q: A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that all the four bulbs are defective.
Options:
(A) 62/63
(B) 125/126
(C) 1/63
(D) 1/42
(E) 1/126
A:
OK... Stream of consciousness: Answer: Option E
Out of nine, five are good and four are defective. Required probability = c/c = 1/126
The answer is (E).