2001 AMC 12 Problems/Problem 9

Revision as of 01:51, 8 February 2009 by Duelist (talk | contribs) (New page: == Problem == Let <math>f</math> be a function satisfying <math>f(xy) = \frac{f(x)}y</math> for all postitive real numbers <math>x</math> and <math>y</math>, and <math>f(500) =3</math>. Wh...)
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Problem

Let $f$ be a function satisfying $f(xy) = \frac{f(x)}y$ for all postitive real numbers $x$ and $y$, and $f(500) =3$. What is $f(600)$?

$(\mathrm{A})\ 1 \qquad (\mathrm{B})\ 2 \qquad (\mathrm{C})\ \frac52 \qquad (\mathrm{D})\ 3 \qquad (\mathrm{E})\ \frac{18}5$

Solution

$f(500\cdot\frac65) = \frac3{\frac{65}} = \frac25$ (Error compiling LaTeX. Unknown error_msg), so the answer is $\mathrm{C}$.