Question:
A rectangular water tank is 90 cm wide and 40 cm deep. If it can contain 576 litres of water, what is its length?
Solution:
Capacity of the water tank $=576$ litres $=0.576 \mathrm{~m}^{3}$
Width $=90 \mathrm{~cm}=0.9 \mathrm{~m}$
Depth $=40 \mathrm{~cm}=0.4 \mathrm{~m}$
Length $==\frac{\text { capacity }}{\text { width } \times \text { depth }}=\frac{0.576}{0.9 \times 0.4}=1.600 \mathrm{~m}$