q: Company Z spent 1/4 of its revenues last year on marketing and 1/7 of the remainder on maintenance of its facilities. What fraction of last year's original revenues did company Z have left after its marketing and maintenance expenditures?
Options:
(A) 5/14
(B) 1/2
(C) 17/28
(D) 9/14
(E) 9/11
a: Stream of consciousness: Total revenues = x
Spent on marketing = x/4
Remaining amount = x-x/4 = 3x/4
1/7 of the remainder on maintenance of its facilities = 3x/4*1/7 = 3x/28
Amount left = 3x/4-3x/28 = 9x/14 The answer is (D).
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q: The average of 13 result is 20. Average of the first 8 of them is 20 and that of the last 8 is 40. Find the 8th result?
Options:
(A) 35
(B) 37
(C) 46
(D) 90
(E) 100
a: Stream of consciousness: Sum of all the 13 results = 13 * 20 = 260
Sum of the first 7 of them = 8 * 20 = 160
Sum of the last 7 of them = 8 * 40 = 320
So, the 8th number = 260 + 160 - 320 = 100. The answer is (E).
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q: Three people took GMAT practice tests in which the minimum and maximum possible scores are 200 and 800, respectively. They each took a test 3 times, and no one scored below 510 or over 780. If the individual ranges of the three people's scores in those 3 practice tests were 20, 90 and 130, what is the difference between the maximum and minimum possible ranges of all their scores put together.
Options:
(A) 70
(B) 80
(C) 90
(D) 140
(E) 170
a:
Stream of consciousness: According to the information in the question the maximum range would be between 510 and 780(270). The minimum range would be the greatest range for any one individual, which is listed in the problem as 130. So the difference between these would be 270-130 or 140. The answer is (D).
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