A swimming pool is `20 m` in length, `15 m` in breadth, and `4m` in depth. Find the cost of cementing its floor and walls at the rate of `R sdot12` per square metre.

Explanation

Given:
`l=20 m`
`b=15 m`
`h=4 m`
Area for cementing`=`Area of `4` walls `+` Area of floor
`=2h(l+b)+lb`
`=2(4)(20+15)+(20×15)`
`=8×35+300`
`=280+300`
`=580 m^2`
Rate of coner of its floor`=Rs.12 perm^2`
`therefore` Total cost of coner its floor `=580×12=Rs.6960`