1986 AJHSME Problems/Problem 11

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Problem

If $\text{A}*\text{B}$ means $\frac{\text{A}+\text{B}}{2}$, then $(3*5)*8$ is

$\text{(A)}\ 6 \qquad \text{(B)}\ 8 \qquad \text{(C)}\ 12 \qquad \text{(D)}\ 16\qquad \text{(E)}\ 30$

Solution

You might have realized that $A*B$ gets you the average of A and B. If you're good at averages, you'll immediately realize that the average of $3$ and $5$ is $4$, and the average of $4$ and $8$ is $6$.

See Also

1986 AJHSME Problems

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