Question

Q2.Find the cost of colour –washing the four walls of aroom whose length is 8m, breadth is7m

and height is 6m at the rate of Rs30 per square metre​

Answer 1

Answer:

Rs 7080

Step-by-step explanation:

It is given that length, breadth and height of a room are 8 m, 7 m and 6 m respectively.

Area of four walls of the room is: 2h(l+b)

A=2h(l+b)=2×6(8+7)=12×15=180 m²  

Area of the ceiling is:  

A=l×b=8×7=56 m²  

Total area of the four walls and the ceiling of the room is 180+56=236m²  

It is given that cost of white washing is Rs.30/m²  

, therefore,

Total cost of white washing is:

236×30=7080

Hence, the cost of white washing the walls is Rs.7080.

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Answer 2

Answer:

• The cost of colour washing a room is Rs. 5400.

Explanation:

Given information,

Find the cost of colour washing the four walls of a room whose length is 8m, breadth is 7m and height is 6m at the rate of Rs. 30 per m².

• Length of room (l) = 8m
• Breadth of room (b) = 7m
• Height of room (h) = 6m

We clearly know that area of four walls also called curved surface area.

Using formula,

✪ CSA of cuboid = 2(l + b)h ✪

Where,

• CSA of cuboid = CSA of room
• l denotes length of room
• b denotes breadth of room
• h denotes height of room

We have,

• Length of room (l) = 8m
• Breadth of room (b) = 7m
• Height of room (h) = 6m
• CSA of room = ?

Putting all values,

➻ CSA of room = 2(8 + 7)6

➻ CSA of room = 2(15)6

➻ CSA of room = 2 × 15 × 6

➻ CSA of room = 30 × 6

➻ CSA of room = 180m²

• Hence, area of four walls of a room is 180m².

We know that,

✪ Cost = Area × Rate ✪

Where,

• Cost denotes cost of colour washing
• Area denotes area of room
• Rate denotes rate of colour washing

We have,

• Area of room = 180m²
• Rate of colour washing = Rs. 30 per m²
• Cost of colour washing = ?

Putting all values,

➻ Cost of colour washing = 180 × 30

➻ Cost of colour washing = Rs. 5400

• Hence, cost of colour washing the four walls of a room is Rs. 5400.

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