swerve wrote: ↑Mon Aug 24, 2020 10:52 am
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
The pull-up totals = the integers between 11 and 25, inclusive.
For any set of consecutive integers:
Count = biggest - smallest + 1
Average = (biggest + smallest)/2
Sum = (count)(average)
In the set above:
Count = 25 - 11 + 1 = 15
Average = (25 + 11)/2 = 18
Sum = (15)(18) = 270
The correct answer is
C.
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