Question

12. A door of length 3 m and breadth 2 m
is fitted in a wall. The length of the
wall is 20 m and the breadth is 8 m.
Find the cost of white washing the wall,
if the rate of white washing the wall is
ruppes 8 per m²​

Answer 1

Answer:

₹1232

Step-by-step explanation:

The area of the door is=3×2

=6m²

The area of the wall is=20×8m

=160m²

Area of wall that needs to be whitewashed=160-6m²

=154m²

Therefore cost of whitewashing=₹154×8

=₹1232

Answer 2

Given

• Dimensions of a door :-
• Length of the door = 3 m
• Breadth of the door = 2 m
• Dimensions of the wall including the door :-
• Length of the wall including the door = 20 m
• Breadth of the wall including the door = 8 m

To find

• Cost of white washing the wall

Solution

Firstly, we will find the area of the wall including the door.

Using formula,

Area = l × b

where,

• l = length of the door including the door
• b = breadth of the door including the door

Substituting the the given values,

⟶ 20 × 8

⟶ 160 m²

• Area of the door including the door = 160 m²

Now, we will find the area of the door.

Using formula,

Area = l × b

Substituting the the given values,

⟶ 3 × 2

⟶ 6 m²

• Area of the wall = 6 m²

Now, we will find the area of the wall.

Area of the wall = Area of wall including the door - Area of the door

⟶ 160 - 6

⟶ 154 m²

• Area of the wall = 154 m²

Cost of whitewashing 1 m² of the wall = Rs. 8

Cost of whitewashing 154 m² of the wall = 154 × 8 = Rs. 1232

Cost of whitewashing the wall = Rs. 1232