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## 2008 AMC12 A #10 본문

AMC12/2008

### 2008 AMC12 A #10

수악중독 2014.12.19 17:11

Doug can paint a room in $5$ hours. Dave can paint the same room in $7$ hours. Doug and Dave paint the room together and take a one-hour break for lunch. Let $t$ be the total time, in hours, required for them to complete the job working together, including lunch. Which of the following equations is satisfied by $t$?

(A) $\left ( \dfrac{1}{5} + \dfrac{1}{7} \right ) (t+1) =1$

(B) $\left ( \dfrac{1}{5} + \dfrac{1}{7} \right ) t +1=1$

(C) $\left ( \dfrac{1}{5} + \dfrac{1}{7} \right ) t =1$

(D) $\left ( \dfrac{1}{5} + \dfrac{1}{7} \right ) (t-1)=1$

(E) $(5+7)t=1$

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