2003 AMC 8 Problems/Problem 5

Problem

If $20\%$ of a number is $12$ , what is $30\%$ of the same number?

$\textbf{(A)}\ 15\qquad\textbf{(B)}\ 18\qquad\textbf{(C)}\ 20\qquad\textbf{(D)}\ 24\qquad\textbf{(E)}\ 30$

$20\%$ of a number is equal to $\frac{1}{5}$ of that number. Let $n$ =the number

$\frac{1}{5}n = 12$ Multiply both sides by 5

$n = 60$

$30\%$ of $n$ is equal to $\frac{3}{10}n = \frac{3}{10}\cdot60 = 3\cdot6 = \boxed{\textbf{(B)}18}$

2003 AMC 8 (Problems • Answer Key • Resources)
Preceded by Problem 4	Followed by Problem 6
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