Question

7. A hall has four walls, each measuring 11.5 m x 7.2 m. It has two doors of height
width 1 m. It also has three windows of size 1 m x 0.5 m. Find the cost of white​

Answer 1

Correct Question :-

A hall has four walls, each measuring 11.5 m x 7.2 m. It has two doors of height  2 m width 1 m. It also has three windows of size 1 m x 0.5 m. Find the cost of white​washing at rate of Rs 65 per meter?

Given :-

Length of the wall = 11.5 m

Breadth of the wall = 7.2 m

Height of the door = 2 m

Width of the door = 1 m

Dimension of the window = 1 m x 0.5 m

To Find :-

The cost of the whitewash.

Analysis :-

At first find the area of the wall and multiply it by 4.

Then find the area of the door and multiply it by 2 and also the area of the windows and multiply it by 3.

Add the area of the doors and the windows and subtract it from the area of wall.

Multiply the cost of whitewashing per meter to the number we got after subtracting.

Solution :-

We know that,

• l = Length
• h = Height
• b = Breadth

By the formula,

$\underline{\boxed{\sf Area \ of \ rectangle=Length \times Breadth}}$

Given that,

Length (l) = 11.5 m

Breadth (b) = 7.2 m

Substituting their values,

Area = 11.5 × 7.2

Area = 82.8 m²

Since there are four walls,

82.8 × 4 = 331.2 m²

Therefore, the area of four walls is 331.2 m².

Area of the door = Length × Breadth

Given that,

Length (l) = 2 m

Breadth (b) = 1 m

Substituting them,

Area = 2 × 1 = 2 m²

Since there are 2 doors,

2 × 2 = 4 m²

Area of window = Length × Breadth

Substituting them,

Area = 1 × 0.5 = 0.5 m²

Since there are 3 windows,

0.5 × 3 = 1.5 m²

Now,

Area of whitewashing = 331.2 - (4 + 0.5 + 1.5)

Area = 325.2

Given that, cost of whitewashing per meter = Rs. 65

Therefore,

Cost of whitewashing the hall = Cost per meter × Area of walls

By substituting,

Cost of whitewashing = 65 × 325.2

Cost = Rs. 21138

Therefore, the cost of whitewashing is Rs. 21138.

Answer 2

Answer:

11.5*7.2*4=331.2

2*1*2=4

1*.5*3=1.5

4+1.5=5.5

331.2-5.5=325.7

325.7*65=21170.5