Question

A tub is $\frac{2}{5}$ full of water. If $10litres$ of water is taken out from it, then it is $\frac{3}{10}$ full. What is the capacity of the tub $?$

Answer 1

Let the total capacity of tub be$xlitres$

Now, total water in tub $=\frac{2}{5}x$

Remaining water in tub after $10litres$ been taken out

$$\begin{gathered} \Rightarrow \frac{2x}{5}-10=\frac{3x}{10} \\ \Rightarrow \frac{2x}{5}-\frac{3x}{10}=10 \\ \Rightarrow \frac{4x-3x}{10}=10 \\ \Rightarrow x=10\times 10 \\ x=100litres \end{gathered}$$$($ ∵ LCM of$5,10$ is$10)$

Hence, total capacity of the tub is $100litres$.