Chapter 6, Problem 11CR

To determine

The solution of the percent problem “what is $40\%$ of $55$ ?” with equation.

Answer to Problem 11CR

  $22$

Explanation of Solution

Given:

The percent problem “what is $40\%$ of $55$ ?”.

Concept used:

To translate a phrase of the form “whatis $A$ percent of $B$ ?” to an equation. First, assume that the numberis $x$ . Then, read the statement is $A\%$ of In “ $A\%$ of the word “of” represents “multiplication”. So, the given statement can be translated in to an equation as follows:

  $\begin{array}{ccccc}x& \text{is}& A\%& \text{of}& B\\ \downarrow & \downarrow & \downarrow & \downarrow & \downarrow \\ x& =& \frac{A}{100}& ·& B\end{array}$

So, the equation becomes $x=\frac{A}{100}·B$ .

Calculation:

Using the concept, the given statement can be translated into an equation as

  $x=40\cdot \frac{1}{100}\cdot 55$ .

Now, solve the equation as follows:

  $\begin{array}{c}x=40\cdot \frac{1}{100}\cdot 55\\ x=\frac{220}{10}\\ x=22\end{array}$

Therefore, the number which is $40\%$ of $55$ is

  $x=22$

Conclusion:

The solution of the percent problem is $22$ .