Question

3. The floor of a rectangular hall has a perimeter 250 m. If the cost of painting the four
walls at the rate of 10 per m² is 15000, find the height of the hall.
(Hint: Area of the four walls =Lateral surface area.]​

Answer 1

Answer:

ANSWER

Given:

Perimeter=250m

⇒Area of 4 walls =2lh+2bh

=2(b+l)h

⇒Perimeter of floor of wall =2l+2b

⇒2(l+b)=250 m

∴ Area of 4 walls =2(l+b)h

=250h m

2

⇒Cost of painting per m

2

area = Rs. 10

⇒Cost of painting 250h m

2

area = Rs(250h×10)

= Rs.2500h

⇒Painting cost of walls = Rs. 15000

⇒2500h=15000

⇒h=

2500

15000

⇒h=6m

Answer 2

Question :-

The floor of a rectangular hall has a perimeter 250 m. If the cost of painting the four walls at the rate of ₹10 per m2 is ₹15000, find the height of the hall.

[Hint: Area of the four walls = Lateral surface area]

Answer :-

A rectangular hall means a cuboid.

Let the length and breadth of the hall be l and b respectively.

∴ Perimeter of the floor = 2(l + b)

⇒ 2(l + b) = 250 m

∵ Area of four walls = Lateral surface area = 2(1 + b) x h, where h is the height of the hall = 250 h m^2

Cost of painting the four walls

= Rs. (10 x 250 h) = Rs. 2500h

⇒ 2500 h = 15000 ⇒ h = 15000/2500 = 6

Thus, the required height of the hall = 6 m

Plz mrk as brainliest ❤