Question

A swimming pool is 20 m in length, 15 m in breadth, and 4 m in depth. Find the cost of cementing it's floor and walls at the rate of rupees 12 per square metre​

Answer 1

Answer:

Rs 6960

Step-by-step explanation:

Given that,

l=20m

b=15m

d=4m (d-h)

We know that,

Area for coner its floor2d(l+b)+lb

=2(4)(20+15)+(20×15)

=8×35+300

=280+300

=580m

2

Rate of coner its floor Rs.12/m

2

∴ Total cost of coner its floor =580×12

Rs.6960

Then,

We get Rs.6960

Answer 2

Given:

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

• Length of the swimming pool = 20 m
• Breadth of the swimming pool = 15 m
• Depth/height of the swimming pool = 4 m

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

To find:

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Cost of cementing its floor and walls at the rate of 12 Rs per square metre.

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Solution:

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

We know that,

Lateral surface area of a cuboid = 2(l + b)h

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

So, area of the four walls of the swimming pool

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

= 2h(l + b)

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Now substitute the known values,

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

2 h(l + b)

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

= {2 × 4 × (20 + 15)} m$^{2}$

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

= 8 × 35 m$^{2}$

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

= 280 m$^{2}$

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Area of the floor of the swimming pool = l × b = 20 × 15 m$^{2}$

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

= 300 m$^{2}$

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

So, total area to be cemented = Area of the four walls of the swimming pool + Area of the floor of the swimming pool.

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Cost of cementing 1 square metre was given that is 12 Rs.

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Therefore, cost of cementing its floor and walls at the rate of rupees 12 per square metre

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

= 12 × 580

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

= Rs 6960.