76% of the students in a school are boys. If the number of girls is 204, then the total number of students is :

Answer: Option C

Let the total number of students be x
Then,
$$\begin{array}{rl}& \left(100-76\right)\%\text{ of }x=204\\ & \Rightarrow 24\%\text{ of }x=204\\ & \Rightarrow \frac{24}{100}x=204\\ & \Rightarrow x=\left(\frac{204\times 100}{24}\right)\\ & \Rightarrow x=850\end{array}$$