Q12 of 24 Page 236

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

Given,


length (l) = 20 m


breadth (b) = 15 m


depth (d) = 4 m


Total area of walls = 2(bd) + 2(ld)


= 2 d (l+b)


= 2 × 4 (20 + 15)


= 280 m2


Area of base = lb


= 20 × 15


= 300 m2


Total area to be cemented = Area of base + Total area of walls


= 300m2 + 280m2


= 580 m2


cost of cementing = Rs 12 per m2


⇒ Total cost of cementing = 12 × 580


= 6960


So, Total cost of cementing of the pool is Rs. 6960


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