The capacity of a cuboidal tank is 50000 litres of water.

Solution:

Let the breadth of the tank be b m.

Length (l) and depth (h) of tank is 2.5 m and 10 m respectively.

Volume of $\operatorname{tank}=1 \times b \times h$

$=(2.5 \times b \times 10) \mathrm{m}^{3}$

$=25 b \mathrm{~m}^{3}$

Capacity of tank $=25 b \mathrm{~m}^{3}=25000 \mathrm{~b}$ litres

$\therefore 25000 b=50000$

$\Rightarrow b=2$

Therefore, the breadth of the tank is 2 m.