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: 45 pupil,out of them 12 in debate only and 22 in singing only.then how many in both?
Options:
(A) 9
(B) 10
(C) 11
(D) 12
(E) 13
answer: Stream of consciousness: The intersection for two = 45 - 12 - 22 = 11 play both games. The answer is (C).
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question: In what time a sum of money double itself at 3% per annum simple interest?
Options:
(A) 33 1/8%
(B) 33 1/3%
(C) 33 3/3%
(D) 33 1/7%
(E) 32 1/3%
answer: Stream of consciousness: P = (P*3*R)/100
R = 33 1/3% The answer is (B).
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question: If 1/2 of the air in a tank is removed with each stroke of a vacuum pump, what fraction of the original amount of air has been removed after 5 strokes ?
Options:
(A) 31/32
(B) 7/8
(C) 1/4
(D) 1/8
(E) 1/16
answer:
Stream of consciousness: Left After 1st stroke = 1/2
Left After 2nd stroke = 1/2 * 1/2 = 1/4
Left After 3rd stroke = 1/2 * 1/4 = 1/8
Left After 4th stroke = 1/2 * 1/8 = 1/16
Left After 5th stroke = 1/2 * 1/16 = 1/32
So removed = 1- 1/32 = 31/32 The answer is (A).
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