Question

A rectangular tank is one-fourth full of water. How much more water ($inc{m}^3$) needs to be added to completely fill it?

Answer 1

Volume of water that needs to be added to make the tank full is the volume of the empty space in the tank. Since the tank is already a quater full, $\frac{3}{4}$ of the tank is empty.

Length of the tank $l=20cm$
Breadth of the tank $b=8cm$
Height of the tank $h=17cm$
Volume of the tank $=l\times b\times h=20\times 8\times 17=2720c{m}^3$

$\therefore \frac{3}{4}$ of the volume of the tank $=\frac{3}{4}\times 2720=2040c{m}^3$

So, $2040c{m}^3$ of water needs to be added to the tank to make it full.