Chapter 12.5, Problem 43STP

To determine

To find: The value of $40\%$

Answer to Problem 43STP

The $40\%$ of $125$ is $50$ .

Explanation of Solution

Given information:

The given equation of $40\%$

Calculation:

Calculate the value:

To find $40\%$ of what number is $50$ .

Consider the number $x$

  $40\%$ of $x$ is $50$ .

Then by algebra, for any number $k$ , $k\%=\frac{k}{100}$ ,

Apply this result,

The $40\%$ can be written as $40\%=\frac{40}{100}.$

So, to find the value $40\%$ of the number $x$ is $50$ .

  $x\times \frac{40}{100}=50$

Multiply by $100$ on both sides:

  $\begin{array}{l}x\times \frac{40}{100}\times 100=50\times 100\\ 40x=50\times 100\end{array}$

Divided by $40$ on both sides;

  $\begin{array}{c}\frac{40x}{40}=\frac{50\times 100}{40}\\ x=\frac{5000}{40}\\ =125\end{array}$

Therefore, the $40\%$ of $125$ is $50$ .