BTGmoderatorDC wrote:If N = 255 is the lowest of a set of 23 consecutive multiples of 15, what is the range of this set?
(A) 315
(B) 330
(C) 345
(D) 360
(E) 375
Range = biggest - smallest = 23rd value - 1st value.
Since the set is composed of consecutive multiples of 15, the difference between one value and the next = 15.
To get from the 1st value to the 2nd value, we must add 15 once.
Thus:
(2nd value) - (1st value) = 15*1 = 15
To get from the 1st value to the 3rd value, we must add 15 twice.
Thus:
(3rd value) - (1st value) = 15*2 = 30
By extension:
To get from the 1st value to the 23rd value, we must add 15 twenty-two times
Thus:
Range = (23rd value) - (1st value) = 15*22 = 330
The correct answer is
B.
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