LM wrote:

What is the sum of the multiples of 7 from 84 to 140, inclusive?

A. 896

B. 963

C. 1008

D, 1792

E. 2016

We can use the following equation to determine the quantity:

(largest multiple in the set - smallest multiple in the set)/7 + 1 = number of multiples of 7

(140 - 84)/7 + 1

56/7 + 1 = 9

Next, let’s determine the average of this evenly spaced set.

average = (first number + last number)/2

average = (84 + 140)/2 = 224/2 = 112

Thus, the sum is 9 x 112 = 1,008.

Answer: C

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Jeffery Miller

Head of GMAT Instruction

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