question: A can do a piece of work in 30 days while B can do it in 40 days. In how many days will they finish it together?
Options:
(A) 120/7
(B) 95/8
(C) 123/9
(D) 150/7
(E) None
answer: Stream of consciousness: 1/30 + 1/40 = 7/120
Both can finish the work in 120/7 days The answer is (A).
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question: A train 400 m in length crosses a telegraph post in 16 seconds. The speed of the train is?
Options:
(A) 22 kmph
(B) 77 kmph
(C) 54 kmph
(D) 71 kmph
(E) 90 kmph
answer: Stream of consciousness: S = 400/16 * 18/5 = 90 kmph The answer is (E).
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question: The no. of girls in a class are 7times the no. of boys, which value cannever be the of total students?
Options:
(A) 20
(B) 35
(C) 30
(D) 40
(E) 42
answer: Stream of consciousness: Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8. The answer is (C).
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question: A train 650 m long is running at a speed of 81 km/hr. In what time will it pass a bridge 340 m long?
Options:
(A) 42
(B) 43
(C) 44
(D) 45
(E) 46
answer:
Stream of consciousness: Speed = 81 * 5/18 = 45/2 m/sec
Total distance covered = 650 + 340 = 990 m
Required time = 990 * 2/45 = 44 se The answer is (C).
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