Difference between revisions of "2012 AMC 10A Problems/Problem 1"
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<math> \textbf{(A)}\ 10\qquad\textbf{(B)}\ 15\qquad\textbf{(C)}\ 20\qquad\textbf{(D)}\ 25\qquad\textbf{(E)}\ 30 </math> | <math> \textbf{(A)}\ 10\qquad\textbf{(B)}\ 15\qquad\textbf{(C)}\ 20\qquad\textbf{(D)}\ 25\qquad\textbf{(E)}\ 30 </math> | ||
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| + | == Solution == | ||
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| + | Cagney can frost one in 20 seconds, and Lacey can frost one in 30 seconds. Working together, they can frost one in <math>\frac{20*30}{20+30} = \frac{600}{50} = 12</math> seconds. In 300 seconds (5 minutes), they can frost <math>\qquad\textbf{(D)}\ 25</math> cupcakes. | ||
Revision as of 18:27, 8 February 2012
Problem 1
Cagney can frost a cupcake every 20 seconds and Lacey can frost a cupcake every 30 seconds. Working together, how many cupcakes can they frost in 5 minutes?
Solution
Cagney can frost one in 20 seconds, and Lacey can frost one in 30 seconds. Working together, they can frost one in 
seconds. In 300 seconds (5 minutes), they can frost 
cupcakes.
