Question

Hameed has built a cubical water tank with lid for his house, with each outer edge 1.5m long. He gets the outer surface of the tank excluding the base, covered with square tiles of side 25cm. Find how much he would spend for the tiles, if the cost of the tiles is ₹360 per dozen.

Answer 1

Since Hameed is getting the five outer faces of the tank covered with tiles, he would need to know the surface area of the tank, to decide on the number of tiles required.
Edge of the cubical tank = 1.5 m = 150 cm (= a)
So, surface area of the tank (excluding base) = 5 × 150 × 150 $c{m}^2$
Area of each square tile = side × side = 25 × 25 $c{m}^2$
So, the number of tiles required= $\frac{surfaceofthetank}{areaofeachtile}=\frac{5\times 150\times 150}{25\times 25}=180$
Cost of 1 dozen tiles, i.e., cost of 12 tiles = ₹ 360
Therefore, cost of one tile = ₹ $\frac{360}{12}=₹30$
So, the cost of 180 tiles = 180 × ₹ 30 = ₹ 5400.