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| − | ==Problem ==
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| − | What is <math>10 \cdot \left(\tfrac{1}{2} + \tfrac{1}{5} + \tfrac{1}{10}\right)^{-1}?</math>
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| − | <math> \textbf{(A)}\ 3\qquad\textbf{(B)}\ 8\qquad\textbf{(C)}\ \frac{25}{2}\qquad\textbf{(D)}}\ \frac{170}{3}\qquad\textbf{(E)}\ 170</math>
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| − | == Solution ==
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| − | Sum the fractions over the common denominator: <math>\dfrac{1}{2}+\dfrac15+\dfrac1{10}=\dfrac{5+2+1}{10}=\dfrac45</math>
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| − | Now the answer is just some arithmetic: <math>10*\left(\dfrac45\right)^{-1}=10*\dfrac{5}{4}= \boxed{\textbf{(C)}\ \dfrac{25}2}</math>
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| − | ==See Also==
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| − | {{AMC12 box|year=2014|ab=A|before=First Problem|num-a=2}}
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| − | {{MAA Notice}}
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Revision as of 20:16, 7 February 2014
Deleted because of duplicate.
