What is the range of a set consisting of the first 100 multi

[BTGmoderatorDC]

What is the range of a set consisting of the first 100 multiples of 7 that are greater than 70?

A. 693
B. 700
C. 707
D. 777
E. 847

OA A

Source: GMAT Prep

[Jay@ManhattanReview]

What is the range of a set consisting of the first 100 multiples of 7 that are greater than 70?

A. 693
B. 700
C. 707
D. 777
E. 847

OA A

Source: GMAT Prep

A few first multiples of 7 that are greater than 70 are 77, 84, 98, ...; we can write them as 7*11; 7*12: 7*13.

So, the first multiple of 7 that is greater than 70 = 7*11;
and the 100th multiple of 7 that is greater than 70 = 7*110

Thus, range = 7*110 - 7*11 = 7(110 - 11) = 7*99 = 693

The correct answer: A

Hope this helps!

-Jay
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[Ian Stewart]

The range of one hundred consecutive multiples of 7 will always be the same no matter what the smallest value in your list is, so we can just find the range of 7, 14, 21..., 693, 700, which is 700-7 =693.