Question

A swimming pool is 20m in length, 15m in breadth and 4m in depth. Find the cost of painting its four walls at the rate of Rs. 20 per square meter.

Answer 1

Hint: Before attempting this question read the given information carefully and find out the shape of the swimming pool and also remember to use the formula\[2\left( {l + b} \right)h\], using this information can help you to approach the solution of the problem.

Complete step-by-step answer:
According to the given information we have a swimming pool with length 20m, breadth of 15m and the 4m depth and we know by the above information the resulting shape of the swimming pool will be

Here to find the cost of painting the four walls we have to find the curved surface area of cuboid
And we also know that formula for the curved surface area of cuboid which is given by \[2\left( {l + b} \right)h\] here l is the length of the cuboid, b is the base of the cuboid and h is the height or depth of the cuboid
Substituting the given values in the formula if curved surface area of cuboid we get
Curved surface area of cuboid = \[2\left( {20 + 15} \right)4\]
$ \Rightarrow $ Curved surface area of cuboid = \[2 \times 35 \times 4\]
$ \Rightarrow $ Curved surface area of cuboid = $280{m^2}$
As it is given that the cost of painting is Rs. 20 per ${m^2}$
Therefore, the cost of painting the four walls of the swimming pool = $20 \times 280$
$ \Rightarrow $ Cost of painting the four walls of the swimming pool = Rs. 5600
Therefore, the cost of painting the four walls of the swimming pool is Rs. 5600

Note: In the above solution we used the term “cuboid” which can be explained as the three-dimensional shape or a polyhedron which consist of 6 faces shape of a rectangle, here the faces are parallel to each other whereas all the faces of cuboid don’t consist of the equal dimensions also in cuboid the faces which are not parallel to each other are named as an adjacent faces.