Question

A swimming pool is 20 m in lenght ,15 m in breadth ,and 4 m in depth . find the cost of cementing its floor and walls at the rate ₹12 per square meter. please solve

Answer 1

l = 20
b = 15
h = 4

Cementing floor and walls area = LSA of cuboid + area of base

= 2h (l+b) + lb
= 2 × 4 (20+15) + 20×15
= 8 (35) + 300
= 280 + 300
= 580 sq. m is the area to be cemented.

cost of Cementing = 12 × 580 = Rs. 6960

hope it helps : )

Answer 2

First find the lsa + lb   ....
.lsa 2h<l+b>  
2*4<20+15>
8*35
280
now lb....
20*15
300
add them 
280+300
580
now cost is 12 per m sq so
....580*12
6960 rupee