Question: 10 books are placed at random in a shelf. The probability that a pair of books will always be together is
Options:
(A) 1/9
(B) 1/7
(C) 1/5
(D) 1/1
(E) 1/2
Ans: (C)
CoT: 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
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Question: The difference between the local value and the face value of 7 in the numeral 32675149 is
Options:
(A) 69950
(B) 69993
(C) 69997
(D) 70000
(E) 01000
Ans: (B)
CoT: (Local value of 7) - (Face value of 7) = (70000 - 7) = 69993
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Question: In a race of 150 m, A gives B a start of 20 m. What distance will be covered by B ?
Options:
(A) 100 m
(B) 130 m
(C) 170 m
(D) 160 m
(E) 180 m
Ans: (B)
CoT: Required distance = (150 - 20) m = 130 m
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