q: There are different 10 circles. What is the number of the greatest possible points with which the circles intersect?
Options:
(A) 90
(B) 100
(C) 110
(D) 180
(E) 200
a: Maximum points of intersection between n different circles = n*(n - 1) = 10*9 = 90 The answer is (A).
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q: There are 7 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) 315
(D) 180
(E) 200
a: Number of ways of selecting 2 fiction books = 7C2
Number of ways of selecting 2 non fiction books = 6C2
7C2 * 6C2 = 21 * 15 = 315 The answer is (C).
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q: Pipe A can fill a tank in 5 hours, pipe B in 10 hours and pipe C in 30 hours. If all the pipes are open, in how many hours will the tank be filled?
Options:
(A) 2
(B) 2.2
(C) 3
(D) 3.5
(E) 4
a: Part filled by A + B + C in 1 hour = 1/5 + 1/10 + 1/30 = 1/3
All the three pipes together will fill the tank in 3 hours. The answer is (C).
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q: A 125 meter long train crosses a man standing on the platform in 5 sec. What is the speed of the train?
Options:
(A) 229
(B) 108
(C) 278
(D) 126
(E) 90
a:
S = 125/5 * 18/5 = 90 kmph The answer is (E).
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