q: A pipe can fill a cistern in 7 minutes whereas the cistern when fill can be emptied by a leak in 14 minutes. When both pipes are opened, find when the cistern will be full?
Options:
(A) 17
(B) 16
(C) 70
(D) 14
(E) 12
a: 1/7 - 1/14 = 1/14
14 minutes The answer is (D).
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q: 80 is increased by 50%. Find the final number.
Options:
(A) 100
(B) 110
(C) 120
(D) 30
(E) 160
a: Final number = Initial number + 50%(original number) = 80 + 50%(80) = 80 + 40 = 120. The answer is (C).
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q: A man, a woman and a boy can complete a job in 3, 4 and 12 days respectively. How many boys must assist 1 man and 1 woman to complete the job in 1/4 of a day?
Options:
(A) 22
(B) 77
(C) 26
(D) 41
(E) 66
a: (1 man + 1 woman)'s 1 day work = (1/3 + 1/4) = 7/12 Work done by 1 man and 1 woman in 1/4 day = (7/12 * 1/4) = 7/48
Remaining work = (1 - 7/48) = 41/48
Work done by 1 boy in 1/4 day = ( 1/12 * 1/4) = 1/48
Number of boys required = 41/48 * 41 = 41. The answer is (D).
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q: In what time will a railway train 60 m long moving at the rate of 36 kmph pass a telegraph post on its way?
Options:
(A) 10 sec
(B) 8 sec
(C) 5 sec
(D) 6 sec
(E) 11 sec
a:
T = 60/36 * 18/5 = 6 sec The answer is (D).
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