A swimming pool 9 m wide and 12 m long and 1 m deep on the shallow side and 4 m deep on the deeper side. Its volume is :

Answer: Option B

Given length of width of swimming pool is 9 m and 12 m respectively
Volume of swimming pool :
$$\begin{array}{rl}& =9\times 12\times \left(\frac{1+4}{2}\right)\\ & =9\times 12\times \frac{5}{2}\\ & =270\text{cu. metre}\end{array}$$