question: A 160 meter long train crosses a man standing on the platform in 16 sec. What is the speed of the train?
Options:
(A) 36 kmph
(B) 54 kmph
(C) 92 kmph
(D) 86 kmph
(E) 76 kmph
answer: Stream of consciousness: S = 160/16 * 18/5 = 36 kmph The answer is (A).
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question: When the price of sugar was increased by 32%, a family reduced its consumption in such a way that the expenditure on sugar was only 10% more than before. If 30 kg were consumed per month before, find the new monthly consumption.
Options:
(A) 20 kg
(B) 25 kg
(C) 30 kg
(D) 35 kg
(E) None of these
answer: Stream of consciousness: Since, expenditure = price consumption
110% of 30 = 132100 new consumption
110100 30 = 132100 new consumption
New consumption = 25 kg The answer is (B).
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question: The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?
Options:
(A) 7
(B) 4
(C) 12
(D) 19
(E) 28
answer: Stream of consciousness: Average of 20 numbers = 0
Sum of 20 numbers = (0 * 20) = 0
It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (-a). The answer is (D).
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question: 10 books are placed at random in a shelf. The probability that a pair of books will always be together is
Options:
(A) 1/6
(B) 1/9
(C) 1/5
(D) 1/6
(E) 1/3
answer:
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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