question: A man rows his boat 90 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 5 kmph
(B) 7 kmph
(C) 9 kmph
(D) 8 kmph
(E) 1 kmph
answer: Stream of consciousness: Speed downstream = d/t = 90/(2 1/2) = 36 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (36 - 18)/2 = 9 kmph The answer is (C).
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question: Find the least number must be subtracted from 531742 so that remaining no.is divisible by 3?
Options:
(A) 4
(B) 5
(C) 1
(D) 2
(E) 3
answer: Stream of consciousness: On dividing 531742 by 3 we get the remainder 1, so 1 should be subtracted The answer is (C).
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question: How many seconds will a train 120 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph?
Options:
(A) 27 sec
(B) 23 sec
(C) 24 sec
(D) 25 sec
(E) 26 sec
answer: Stream of consciousness: D = 120 + 150 = 270
S = 36 * 5/18 = 10 mps
T = 270/10 = 27 sec The answer is (A).
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question: In a bucket there are 3 blue balls and 2 red balls. What is the probability of drawing at least one blue ball when drawing two consecutive balls randomly?
Options:
(A) 9/10
(B) 16/20
(C) 2/5
(D) 3/5
(E)
answer:
Stream of consciousness: P(at least one blue) = 1 - P(no blue, so 2 red) = 1- 2/5*1/4 = 9/10. The answer is (A).
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