A room is of length 5 metres, breadth 3.5 metres and height 4 metres.

1.	A room is of length 5 metres, breadth 3.5 metres and height 4 metres. Find the cost of white washing the four walls and the roof at the rate of Rs 15 per square metre.
Answer» Area of four walls = 2(l + b) x h = 2[5 + 3.5] x 4 = 8.5 x 8 = 68.0 sq. m Area of roof = l x b = 5 x 3.5 = 17.5 m² Total area = 17.5 + 68 = 85.5 m² Cost of expenditure per square metre is Rs. 15 Cost of expenditure of 85.5 sq. m = 85.5 x 15 = Rs. 1282.5

A room is of length 5 metres, breadth 3.5 metres and height 4 metres. Find the cost of white washing the four walls and the roof at the rate of Rs 15 per square metre.

Answer»

Area of four walls = 2(l + b) x h

= 2[5 + 3.5] x 4

= 8.5 x 8 = 68.0 sq. m

Area of roof = l x b = 5 x 3.5 = 17.5 m²

Total area = 17.5 + 68 = 85.5 m²

Cost of expenditure per square metre is Rs. 15

Cost of expenditure of 85.5 sq. m

= 85.5 x 15

= Rs. 1282.5