Question

How many planks of dimensions (5 m × 25 cm × 10 cm) can be stored in a pit which is 20 m long, 6 m wide and 50 cm deep?
(a) 480
(b) 450
(c) 320
(d) 360

Answer 1

(a) 480

Length of the pit = 20 m
Breadth of the pit = 6 m
Height of the pit = 50 cm = 0.5 m

Length of the plank = 5m
Breadth of the plank = 25 cm = 0.25 m
Height of the plank = 10 cm = 0.1 m

∴ Number of planks = $\frac{\mathrm{volume}\mathrm{of}\mathrm{the}\mathrm{pit}}{\mathrm{volume}\mathrm{of}1\mathrm{plank}}$

$$\begin{gathered} =\frac{20\times 6\times 0.5}{5\times 0.25\times 0.1} \\ =\frac{60\times 1000}{125} \\ =480 \end{gathered}$$