q: A and B together can do a work in 6 days. If A alone can do it in 15 days. In how many days can B alone do it?
Options:
(A) 7
(B) 13
(C) 19
(D) 10
(E) None
a: Stream of consciousness: 1/6 â€“ 1/15 = 1/10
B can do the work in 10 days The answer is (D).
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q: A wheel rotates 20 times every minute and moves 20 cm during each rotation. How many metres does the wheel move in one hour?
Options:
(A) 4 metre
(B) 12 metre
(C) 240 metre
(D) 2400 metre
(E) 130 metre
a: Stream of consciousness: Number of times wheel moves in 1 hour = 20 * 60 = 1200
:. Distance moves = (1200*20) cms = 24000 cms
In metres = 240 metre The answer is (C).
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q: 10 books are placed at random in a shelf. The probability that a pair of books will always be together is ?
Options:
(A) 1/8
(B) 1/2
(C) 1/5
(D) 1/5
(E) 1/3
a:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Stream of consciousness: 10 books can be rearranged in 10! ways consider the two books taken as a pair then number of favourable ways of getting these two books together is 9! 2!
Required probability = 1/5 The answer is (C).
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