How many numbers between 10 - 99 yield a reminder of 8 when divided by 10 and also yield a remainder of 2 when divided by 8?
Options:
(A) One
(B) Three
(C) Two
(D) Five
(E) Four
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Answer = B) Three
Numbers between 10 - 99 giving remainder 8 when divided by 10 = 18, 28, 38, 48, 58, 68, 78, 88, 98
The above Numbers giving remainder 2 when divided by 8 = 18, 58, 98 = 3 So the answer is: (B).
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10 books are placed at random in a shelf. The probability that a pair of books will always be together is?
Options:
(A) 1/7
(B) 1/9
(C) 1/5
(D) 1/8
(E) 1/2
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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 So the answer is: (C).
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The average of 13 numbers is 60. Average of the first 7 of them is 55 and that of the last 7 is 61. Find the 8th number?
Options:
(A) 32
(B) 83
(C) 45
(D) 53
(E) 64
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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
Sum of all the 13 numbers = 13 * 60 = 780
Sum of the first 7 of them = 7 * 55 = 385
Sum of the last 7 of them = 7 * 61 = 427
So, the 8th number = 427 + 385 - 780 = 32. So the answer is: (A).
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