2005 AMC 10A Problems/Problem 1

Revision as of 19:55, 5 February 2010 by Limac (talk | contribs) (Problem)

Problem

While eating out, Mike and Joe each tipped their server $2$ dollars. Mike tipped $10\%$ of his bill and Joe tipped $20\%$ of his bill. What was the difference, in dollars between their bills?

$\mathrm{(A) \ } 2\qquad \mathrm{(B) \ } 4\qquad \mathrm{(C) \ } 5\qquad \mathrm{(D) \ } 10\qquad \mathrm{(E) \ } 20$

Solution

Let $m$ be Mike's bill and $j$ be Joe's bill.

$\frac{10}{100}m=2$

$m=20$

$\frac{20}{100}j=2$

$j=10$

So the desired difference is $m-j=20-10=10 \Rightarrow D$

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