The cost of painting the four walls of a room 12 m long at ₹ 30 per

1.	The cost of painting the four walls of a room 12 m long at ₹ 30 per m2 is ₹ 7560 and the cost of covering the floor with mat at ₹25 per m2 is ₹ 2700. Find the dimensions of the room.
Answer» Length of a wall = 12 m Cost per meter = ₹30 Total cost = ₹ 7560 Cost per meter for floor = ₹ 25 Total cost for floor = ₹ 2700 Let h be the height. Breadth = (area of the floor) / Length = 108/12 = 9m Area of the floor = (total cost)/ (cost per meter) = 2700/25 = 108 m² Again, Area of walls = (total cost)/ (cost per meter) = 7560/30 = 252 m² Now, Area of 4 walls = 2(Length of walls × Height of walls) + 2(Breadth of walls × Height of walls) 252 = 2(12 × h) + 2(9 × h) 252 = 24h + 18h 252 = 42h h = 6 ⇨ Height is 6 m Therefore dimensions of the room are : 12 m × 9 m × 6 m

The cost of painting the four walls of a room 12 m long at ₹ 30 per m2 is ₹ 7560 and the cost of covering the floor with mat at ₹25 per m2 is ₹ 2700. Find the dimensions of the room.

Answer»

Length of a wall = 12 m

Cost per meter = ₹30

Total cost = ₹ 7560

Cost per meter for floor = ₹ 25

Total cost for floor = ₹ 2700

Let h be the height.

Breadth = (area of the floor) / Length = 108/12 = 9m

Area of the floor = (total cost)/ (cost per meter) = 2700/25 = 108 m²

Again,

Area of walls = (total cost)/ (cost per meter) = 7560/30 = 252 m²

Now,

Area of 4 walls = 2(Length of walls × Height of walls) + 2(Breadth of walls × Height of walls)

252 = 2(12 × h) + 2(9 × h)

252 = 24h + 18h

252 = 42h

h = 6

⇨ Height is 6 m

Therefore dimensions of the room are : 12 m × 9 m × 6 m