q: A and B can do a work in 5 days and 10 days respectively. A starts the work and B joins him after 3 days. In how many days can they complete the remaining work?
Options:
(A) 4/3 days
(B) 2 days
(C) 8 days
(D) 3 days
(E) 9 days
a: Stream of consciousness: Work done by A in 3 days = 3/5
Remaining work = 2/5
Work done by both A and B in one day = 1/5 + 1/10 = 3/10
Remaining work = 2/5 * 10/3 = 4/3 days. The answer is (A).
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q: A train running at the speed of 60 km/hr crosses a pole in 9 seconds. Find the length of the train?
Options:
(A) 150
(B) 781
(C) 767
(D) 277
(E) 266
a: Stream of consciousness: Speed = 60*(5/18) m/sec = 50/3 m/sec
Length of Train (Distance) = Speed * Time
(50/3) * 9 = 150 meter The answer is (A).
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q: There are 6 fictions and 6 non-fictions. How many cases are there such that 2 fictions and 2 non-fictions are selected from them?
Options:
(A) 90
(B) 120
(C) 225
(D) 180
(E) 200
a:
Stream of consciousness: Number of ways of selecting 2 fiction books = 6C2
Number of ways of selecting 2 non fiction books = 6C2
6C2 * 6C2 = 15 * 15 = 225 The answer is (C).
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