question: The average of 9 results is 50. The average of first four results is 52 and average of last four results is 49 . what is the fifth result?
Options:
(A) 22
(B) 27
(C) 29
(D) 46
(E) 92
answer: Stream of consciousness: Total of results = 50 x 9 = 450
Total of first four results = 52 x 4 = 208
Total of Last four results = 49 x 4 = 196
Hence the fifth result = 450 - (208 + 196) = 46 The answer is (D).
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question: If the average (arithmetic mean) of the four numbers K, 2K + 3, 3K 5 and 5K + 1 is 85, what is the value of K?
Options:
(A) 11
(B) 15 3/4
(C) 31
(D) 23
(E) 25 3/10
answer: Stream of consciousness: K + 2K +3 + 3K - 5 + 5K +1 = 11K -1
(11K -1)/4 = 85
11K = 85 * 4 +1 = 340 +1 = 341
K = 253 / 11 = 31. The answer is (C).
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question: There are four prime numbers written in ascending order of magnitude. The product of the first three is 7429 and of the last three is 12673. Find the fourth number?
A. 17 B. 29 C. 23 D. 31
Options:
(A) 17
(B) 29
(C) 23
(D) 31
(E) 33
answer: Stream of consciousness: (7429/12673) = 17/29 Fourth Number is 29 The answer is (B).
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question: If x is a positive odd integer and y is a negative even integer, which of the following must be true?
Options:
(A) x^3 + y is a positive odd integer
(B) x^2 + y^2 is a negative odd integer
(C) x^0 + y^11 is a negative odd integer
(D) x + y is a positive odd integer
(E) x + y is a negative odd integer
answer:
Stream of consciousness: Anything power 0 is always 1 and given that Y is even and negative, then
1 + (-2) will be negative with odd power values for Y. The answer is (C).
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