Question

Swimming pool is 20 m in length 15 m in breadth and 4 m in depth find the cost of cementing its floor and four walls at the rate 6 rupees 12 per metre square

Answer 1

Area of 4 walls of the swimming pool

= 2h (l + b)
= 2*4 (20 + 15)
= 8 * 35
= 280 m²

Area of the floor of the swimming pool

= l * b
= 20 * 15
= 300 m²

TOTAL AREA

= 280+300
= 580 m²

Cost of cementing the swimming pool @ Rs. 12/m²

= 580 * 12
= Rs. 6960

(i couldn't understand in that portion where you wrote "at the 6 rupees 12".so here i just assume that the cost is 12 rupees. But this is not the matter. The matter is about the process. You just follow the process only.)