Question

Find the area of the four walls of a room whose length is 6 m, breadth 5 m and height 4 m. Also find the cost of white - washing the walls, if the rate of white washing is 5 rupees per square metre. (doors, windows and other openings ignored).​

Answer 1

Answer:

Area of four walls = 88 m²

cost of white washing the wall = ₹ 440

Step-by-step explanation:

Area = 2(5*4) + 2(6*4)

Area = 88 m²

1 m² = ₹ 5

88 m² = X

X = 5*88

X = ₹ 440

Answer 2

Given:

• Length of the four walls of the room = 6 m
• Breadth = 5 m
• Height = 4 m
• Rate of whitewashing is 5 Rs per square metre.

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To find:

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Area of the four walls of the room and cost of white - washing the walls.

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Solution:

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We know that,

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Lateral surface area of the cuboid = 2h(l + b)

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So, area of the four walls of the room = 2h(l + b)

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= {2 × 4 × (6 + 5)}m$^{2}$

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= (8 × 11)m$^{2}$

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= 88 m$^{2}$

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Cost of white washing of 1 square metre is given that is Rs 5 per metre.

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Therefore, cost of white washing the walls =

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5 × 88

= Rs 440.

More formulas:

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For cuboid:

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Total surface area of the cuboid

= 2(lb + bh + lh)

Lateral surface area of the cuboid

= 2(l + b)h