Question

At the "$30\%$ off" book sale, a calculus book costs $\$24$. What is the original price of the book?

• A. $\$72.80$
• B. $\$77$
• C. $\$80$
• D. $\$82.60$

Answer 1

The correct option is C $\$80$

Let the original price of the book be $x$.

After $30\%$ discount on the original price the rate is 24 $

Therefore, $30\%$ on $x$ is 24$

$\Rightarrow \frac{30}{100}\times$ $x$=$24$

$\Rightarrow \frac{3}{10}\times$ $x$=$24$

$\Rightarrow x=\frac{24\times 10}{3}$

$\Rightarrow x=\frac{240}{3}$

$\Rightarrow x=$80 $