Question

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 ONLY IF YOU KNOW​

Answer 1

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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Answer 2

$\bf\huge\blue{ANSWER}$

$\bf{Here \: we \: know \: that }$

$\small \text \green{length is 8m}$

$\small \text \pink{breadth is 7m}$

$\small \text \blue{height is 6m}$

$\bf\huge\pink{Now}$

$\bf\gray{Area \: of \: four \: wall \: of \: room}$

$\bf{ = 2(l + b) h}$

$\bf \orange{= 2 \times (8 + 7) \times 6}$

$\bf \green{ = 12 \times( 15) = 180 \: {m}^{2} }$

$\bf\huge\purple{Given}$

$\small \text \red{Cost of colour-washing \:1 \: sq. m}$

$\large\boxed{ = 30 \: Rs }$

$\bf\huge\green{Therefore}$

$\small \text \purple{Cost of colour-washing four walls of a room}$

$= \bf{30 \times 180 = 5400 \: Rs}$

$\large\boxed{ = 5400 \: Rs }$

$\small\text{is the answer}$

$\bf\huge\blue{Thanks}$