For any set of consecutive integers:
count = biggest - smallest + 1.
average = (biggest + smallest)/2.
sum = (count)(median).
M7MBA wrote:Bob is training for a fitness competition. In order to increase his maximum number of pull-ups, he follows the following routine: he begins with 25 pull-ups, rests for thirty seconds, and then does 24 pull-ups and rests, dropping one pull-up each time (25, 24, 23, etc.) until his final set of 11 pull-ups. How many total pull-ups does Bob do?
(A) 55
(B) 150
(C) 270
(D) 275
(E) 325
Since Bob starts with 25 pull-ups and drops 1 pull-up each round until his final set of 11 pull-ups, the pull-ups are composed of the consecutive integers between 11 and 25, inclusive.
Thus:
count = 25 - 11+ 1 = 15.
average = (25+11)/2 = 18.
sum = 15*18 = 270.
The correct answer is
C.
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