Question

Find the number of students in your class if its $45\%$ is $18$

Answer 1

We know that

$\frac{Part\left(is\right)}{Whole\left(or\right)}=\frac{Percent}{100}$

Given percent$=45\%$ Part$=18$

$\therefore \frac{18}{Whole}=\frac{45}{100}$

Cross multiply.

$$\begin{gathered} 18\times 100=45\times Whole \\ Whole=\frac{18\times 100}{45} \\ Whole=40 \end{gathered}$$

Therefore, $45\%$ is $18$ of $40$

Hence, the number of students in your class $40$