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Question

The arithmetic mean (or average) of A, B and C is 10. The value of A is six less than the value of B, and the value of C is three more than the value of B. What is the value of C?

Accepted Answer

We know that A+B+C3 = 10, thus, A+B+C = 30. We also know that B = C - 3, and that A = B - 6 = C - 9. Thus, (C - 9) + (C - 3) + C = 30, thus, 3C = 42 C = 14.