Question

a swimming pool is 25 m long 20 m wide and 2 m deep find the cost of cementing its floor and four walls at the rate of ₹20 per m^2​

Answer 1

Given :-

◉ A swimming pool of dimensions:

• Length, l = 25 m
• Breadth, b = 20 m
• Height, h = 2 m

◉ Cost of cementing the floor = ₹ 20 per m²

To Find :-

◉ Cost of cementing its floor and the four walls

Solution :-

Since the swimming pool is in the shape of a cuboid ( dimensions are distinct ),

∴ Total Surface Area = 2(lb + bh + lh)

Now, We need to cement the floor and the four walls, Therefore we need to exclude the surface area of the roof ( which is not present in a swimming pool ).

⇒ Required Surface area = 2(lb + bh + lh) - lb

⇒ SA = 2h(l + b) + lb

⇒ SA = 2×2 ( 25 + 20 ) + 25 × 20

⇒ SA = 4×45 + 500

⇒ SA = 180 + 500

⇒ SA = 680 m²

It is given that the cost of cementing 1 m² is ₹ 20

⇒ Total cost = Area × 20

⇒ Total cost = 680 × 20

⇒ Total cost = ₹ 13,600

Hence, The cost of cementing its floor and the four walls is ₹ 13,600

Answer 2

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ᎶᎨᏉᎬᏁ

Length = 25 m

Breadth = 20 m

Height = 2 m

Cost of cementing 1 m² = ₹20

ᏕᎾᏝᏬᎿᎨᎾᏁ

Area of floor and four walls = CSA + lb

Area of floor and four walls = 2(l+b)h + lb

Area of floor and four walls = 2(25+20)2 + 25×20

Area of floor and four walls = 4(45) + 500

Area of floor and four walls = 180 + 500

Area of floor and four walls = 680 m²

Cost of cementing 680 m² = 680×20

Cost of cementing 680 m² = ₹13600

∴ Your answer = ₹13,600