Question

The weight of a cubic metre of a certain metal is 480 kg. It is melted and then rolled into a square bar 4 m long. Now an exact cube is cut from it. Find the weight of the cube.

(a) 240 kg

(b) 80 kg

(c) 120 kg

(d) 60 kg

Answer 1

Correct option is (d) 60 kg

Weight of a cubic meter = 480kg

It is melted and then rolled into a square bar 4m long.

∴ Volume of square bar = 4 × 1 × 1 = 4m³

Now, a cube is cut from it.

∴ Volume of cube = 1 × 1 × 1 = 1m³

Now, 4m³ weighs 480kg

∴ 1m³ weighs = \(\frac{480}4 \) = 60kg