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Revision as of 11:00, 4 July 2013

Problem 3

Suppose [$a$ $b$] denotes the average of $a$ and $b$, and {$a$ $b$ $c$} denotes the average of $a$, $b$, and $c$. What is {{1 1 0} [0 1] 0}?

$\textbf{(A)}\ \frac{2}{9} \qquad\textbf{(B)}\ \frac{5}{18} \qquad\textbf{(C)}\ \frac{1}{3} \qquad\textbf{(D)}\ \frac{7}{18} \qquad\textbf{(E)}\ \frac{2}{3}$

Solution

Average $1$, $1$, and $0$ to get $\frac23$. Average $0$, and $1$, to get $\frac12$. Average $\frac23$, $\frac12$, and $0$. to get $\boxed{\textbf{(D)}\ \frac7{18}}$

See Also

2011 AMC 10A (Problems • Answer Key • Resources)
Preceded by
Problem 2 		Followed by
Problem 4
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All AMC 10 Problems and Solutions

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