Question

A door of length 2m and breadth 1m and window of length 1m and breadth 0.5m are fit in a wall of length 4.5m and breadth 4m . Find the cost of white washing the wall at the rate of 20 per m square

Answer 1

Answer

Area of rectangular door=length×breadth=2m×1m=2m

2

Area of wall including door=length×breadth=4.5m×3.6m=16.2m

2

Now, Area of wall excluding door

=Area of wall including door−Area of door

=16.2−2=14.2m

2

Since, The rate of white washing of 1m

2

the wall=Rs. 20

Therefore, the rate of white washing of 14.2m

2

the wall=20×14.2

=Rs. 284

Thus, the cost of white washing the wall excluding the door is Rs. 284.

Answer 2

Stated:-

• Length of door is 2m
• Breadth of door is 1m
• Square window dimension is 0.3m
• Length of the wall is 4.5m
• Breadth of the wall is 3.6m

To Attain:-

Cost of whitewashing at per rate of ₹20m²

Formulae to be used:-

• Area of Rectangle = lb sq.units
• Area of Square = (side)²

Where:-

• L stands for length
• B squares for Breadth

Explanation:-

In this Question, we have been provided with the dimensions of the wall,the door and the window and said that we should find the cost of whitewashing the wall! So, let's find the area of the wall and then the area of the door and the window and subtract it from the area of the wall and later multiply the remaining area with rate of whitewashing the wall per m².

Solution:-

According to the question, We will first find the area of wall by using the appropriate formula of Area of Rectangle.

$\longmapsto\sf{Area_{(Rectangle)} = l \times b}$

$\longmapsto\sf{Area = 4.5 \times 3.6}$

$\longmapsto\underline{\sf{\red{Area = 16.20 {m}^{2}}}}$

Now, We will find the area of door by using the same formula

$\longmapsto\sf{Area_{(Rectangle)} = l \times b}$

$\longmapsto\sf{Area = 2\times 1}$

$\longmapsto \underline{\sf{\red{Area = 2{m}^{2}}}}$

Since, we have the known values of given area of wall and door. Now, we will find the area of Square window of dimension that fitted in a wall.

$\longmapsto\sf{Area_{ \: (Square )} = (side)^{2}}$

$\longmapsto\sf{Area = 0.3 \times 0.3}$

$\longmapsto \underline{\sf{\red{Area = 0.09{m}^{2}}}}$

Henceforth, we will now find area of whitewashing in order to find the cost of whole whitewashing

Area to be washed = Area of wall - (Area_door + Area of window)

$\longmapsto\sf{16.2 - (2 + 0.09)}$

$\longmapsto\underline{\sf{\red{ 14.11{m}^{2}}}}$

Now, Let's find the cost of whitewashing at rate of ₹20m²

Rate of whitewashing = ₹20 per m²

Cost of whitewashing = 14.11 × 20

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀= ₹282.20

Final Answer -

⠀⠀⠀ Cost of whitewashing at per rate of ₹20m is ₹282.20

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