Question

On a college math test, 18 students earned an A. This number is exactly $30\%$of the total number of students in the class.State how many students are in the class.

A. $5$ B. 23

C. $48$ D. 60

Short answer

Number of students in the class is 60 and the correct option isD.

Step-by-step solution

- State the definition of a variable.

A variable is a term that is used to represent an unknown value.

Here, let x be the number of students in the class.

- Evaluate the value of x.

It is know that, 18 students got an A and these 18 students are $30\%$of total number of students.

Since x is the total number of students in the class.

Then, $30\%$of x is 18. That is,

$\frac{30}{100}\times x=18$

Simplify the equation using multiplication and division,

$\begin{array}{c}\frac{30}{100}\times x\times 100=18\times 100\\ 30x=1800\\ \frac{30x}{30}=\frac{1800}{30}\\ x=60\end{array}$

Hence, the value of x is 60 that is number of students in the class is 60.

- State the conclusion.

The number of students in the class is 60. Therefore, option D is correct.