Question

A room is 8.5 m long, 7m long and 4m heigh. it has one door measuring 1m by 1m and two windows each measuring 0.5m by 0.5 m. find the cost of painting its four walls without door and windows, if the rate of painting is ₹ 2 per square metre.
Hellwos​

Answer 1

Answer:

A room is 8.5 m long, 7m long and 4m heigh. it has one door measuring 1m by 1m and two windows each measuring 0.5m by 0.5 m. find the cost of painting its four walls without door and windows, if the rate of painting is ₹ 2 per square metre.

say the correct name Ahhh !!

itz Ananya

Answer 2

Answer:

245 rupees

Step-by-step explanation:

Logically, we always paint the 4 walls and the roof of any room or enclosure of such. But since the question requires us to only paint 4 walls, it simplifies things significantly. We can say that the lateral surface area of the room needs to be painted, and only on the inside.

Since, the length, breadth and height are given, naturally, this room is a cuboid. Therefore, its lateral surface area is

2(lxh)+2(bxh)                  (Draw a cuboid to understand better)

2(8.5*4)+2(7*4)

2(34)+2(28)

68+56

124$m^{2}$

But this of course is the total area of the 4 walls. We need to exclude the door and 2 windows.

The door's area being 1$m^{2}$ and the area of 2 windows being 2(0.5*0.5); which is 0.5$m^{2}$ making the total area to be excluded 1.5$m^{2}$.

Thus, the area to be painted is 124-1.5=122.5$m^{2}$

We have been told that the cost of painting is 2 rupees for every metre square. Therefore, for 122.5$m^{2}$ it will be 122.5*2=245 rupees.