Chapter 11.5, Problem 54STP

To determine

To calculate: To find how many cards did S sell

Answer to Problem 54STP

The number of cards sold by S is $72$

Explanation of Solution

Given information: S bought cards at $6$ for $\$10$ . She decorated them and sold them at $4$ for $\$10$ . She made $\$60$ in profit

Calculation:

Given S bought cards at $6$ for $\$10$ .

Thus, cost price of one card is calculated as

  $\begin{array}{l}CP=\frac{\$10}{6}\\ CP=\$1.67\end{array}$

Also, S sold them at $4$ for $\$10$

Thus, selling price of card is calculated as

  $\begin{array}{l}SP=\frac{\$10}{4}\\ SP=\$2.50\end{array}$

Profit on one card is calculated as follows:

  $\begin{array}{l}Profit=SP-CP\\ Profit=2.5-1.67\\ Profit=0.83\end{array}$

Let the number of cards sold by S be $x$

Given that total profit is $\$60$

Thus, number of cards sold by S is calculated as

  $\begin{array}{l}x=\frac{\$60}{\$0.83}\\ x=72.2\\ x\approx 72\end{array}$

Conclusion:

Hence, number of cards sold by S is $72$