q: A 240 meter long train crosses a man standing on the platform in 6 sec. What is the speed of the train?
Options:
(A) 228
(B) 144
(C) 1266
(D) 188
(E) 211
a: Stream of consciousness: S = 240/6 * 18/5 = 144 kmph The answer is (B).
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q: Calculate the speed of a boat in still water (in km/hr) if in one hour, the boat goes 15 km/hr downstream and 7 km/hr upstream.
Options:
(A) 12 kmph
(B) 13 kmph
(C) 14 kmph
(D) 15 kmph
(E) 11 kmph
a: Stream of consciousness: Speed in still water = (15 + 7)1/2 kmph = 11 kmph. The answer is (E).
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q: Two persons A and B can complete a piece of work in 30 days and 45 days respectively. If they work together, what part of the work will be completed in 4 days?
Options:
(A) 2/5
(B) 1/6
(C) 1/4
(D) 1/9
(E) 2/9
a:
Stream of consciousness: A's one day's work = 1/30
B's one day's work = 1/45
(A + B)'s one day's work = 1/30 + 1/45 = 1/18
The part of the work completed in 4 days = 4 (1/18) = 2/9. The answer is (E).
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