Question

a swimming pool is 40m long ,25m broad and 4m deep what is the cost of cementing its floor and sides at the rate of rs 20per m sq

Answer 1

volume is equal to 40*25*4=4000m square
cost of cementing at re 20 is equal to 4000*20=rs80000.
Hope it will help you.
if not clear your doubts by comments.

Answer 2

Hello Friend !

The answer is given below:

Given: Length (l) = 40 m 
          
           Breadth (b) = 25 m

           Height (h) = 4 m

If we find the area of the floor , then this is equal to l × b 

⇒ area of floor = 40 × 25 = 1000 m²

If we find the lateral surface area of the sides , then it is equal to
 = 2(lb + bh + lh)

⇒ lateral surface area of walls = 2( 40×25 + 25×4 + 4×40 ) = 2 × 1260 

⇒ 2520 m²
 
Therefore total area cemented = 

⇒ area of floor + lateral surface area of sides

⇒ 1000 + 2520 = 3520 m²

Since cost of cementing per m² = Rs 20

Therefore cost of cementing 3520 m² = Rs 20 × 3520 m² = Rs 70400

This is your answer.

Hope this helps !