# 1988 AJHSME Problems/Problem 23

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## Problem

Maria buys computer disks at a price of $4$ for $5$ and sells them at a price of $3$ for $5$. How many computer disks must she sell in order to make a profit of $100$?

$\text{(A)}\ 100 \qquad \text{(B)}\ 120 \qquad \text{(C)}\ 200 \qquad \text{(D)}\ 240 \qquad \text{(E)}\ 1200$

## Solution

This is the equivalent of saying she buys $12$ for $15$ and sells $12$ for $20$, so for every dozen disks she sells, she profits $5$.

She needs to profit $100$, so she needs to sell $\frac{100}{5}=20$ dozen disks, which is $240\rightarrow \boxed{\text{D}}$

## See Also

 1988 AJHSME (Problems • Answer Key • Resources) Preceded byProblem 22 Followed byProblem 24 1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 All AJHSME/AMC 8 Problems and Solutions

The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions.

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