Question

A beam 9 m long, 40 cm wide and 20 cm high is made up of iron which weighs 50 kg per cubic metre. The weight of the beam is
(a) 27 kg
(b) 48 kg
(c) 36 kg
(d) 56 kg

Answer 1

(c) 36 kg
Length = 9 m
Breadth = 40 cm = 0.4 m
Height = 20 cm = 0.2 m
∴ Weight of the beam = volume of the beam $\times$weight of iron per cubic metre
$$\begin{gathered} =9\times 0.4\times 0.2\times 50 \\ =36\mathrm{kg} \end{gathered}$$