Question

A cubical tank of edge 30 cm is completely filled with water. If 2.7 litres of water is taken out from the tank. Find the height of the remaining water inside the tank.

Answer 1

Given:

A cubical tank with an edge length of 30 cm is completely filled with water. 2.7 litres of water are taken out.

Convert litres to cubic centimetres

1 litre = 1000 cm³

So 2.7 L = 2.7 × 1000

= 2700 cm³

Volume of the cube (initial water volume)

V_cube = edge³ = 30³

= 27,000 cm³

Volume of water remaining

= 27,000 − 2,700

= 24,300 cm³

Cross-sectional area of the base of the tank

A_base = edge × 30 

= 30 × 30

= 900 cm²

Height of remaining water (h)

h = V ÷ A

= 24,300 ÷ 900

= 27 cm