Question

A swimming pool is 20m in length,15m in breadth and 4m in depth.Find the cost of cementing its floor and wall at the rate of Rs.12 per square metre?

Answer 1

area of four walls and floor=2(l+b)h+l*b
=2(20+15)4+20*15=580msq
cost=580*12=6960rupees

Answer 2

The Total Surface Area of the swimming pool: 2(lb+bh+hl) - lb { excluding the top }
where l is the length
b is the breadth
h is the hieght / depth
2( 20×15 + 15×4 + 4×20 ) - 20×15
2( 300 + 60 + 80 ) - 300
2( 440 ) - 300
880 - 300
580 sq.m
Cost of cementing Rs 12 per sq.m
Cost = 12 × 580
= 6960 Rs