What is the average of the first six multiples of 11?

A27.5

B40.5

C38.5 ✓ Correct

D51.5

Correct answer: (C) 38.5

Explanation

The average is 38.5.

The first six multiples of 11 are 11, 22, 33, 44, 55, 66.

Their sum is 11 x (1 + 2 + 3 + 4 + 5 + 6) = 11 x 21 = 231.

Dividing by 6 gives 231/6 = 38.5.

The mean of an evenly spaced set is (11 + 66)/2 = 38.5.

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