Question

Fill the blank space $\frac{3}{5}=\frac{x}{20}$

Answer 1

Consider that the unknown number be $x$

Therefore,

$\frac{3}{5}=\frac{x}{20}$

Cross multiply,

$\begin{array}{c}\frac{3\times 20}{5}=x\\ x=12\end{array}$

hence, $x=12$