Question

a room is 8m long, 6m wide and 3.5m high.Find the cost of white-washing it's four walls at the rate of Rs 50 per square metre.
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Answer 1

..Question..

A room is 8 m long , 6 m wide and 3.5 m high . Find the cost of white-washing it's for wall at the rate of Rs 50 per sq. m .

..Answer..

Given here ,

ㅤㅤㅤㅤ➪ Length = 8 metre

ㅤㅤㅤㅤ➪ Breadth = 6 metre

ㅤㅤㅤㅤ➪ Height = 3.5 metre

♧︎︎︎ First ,

☯︎ We are to find ☞︎︎︎ Surface area

°•° Surface area of cuboid = 2(lb + bh + hl)

ㅤㅤ•°• putting the values , we get

➪ 2 ( lb + bh + hl )

➪ 2 { ( 8•6 ) + ( 6•3.5 ) + ( 3.5•8 ) }

➪ 2 ( 48 + 21 + 28 )

➪ (2 × 48) + (2 × 21) + (2 × 28)

➪ 96 + 42 + 56

➪ 96 + 98

➪ 194 ㅤㅤㅤㅤㅤ

•°• Surface area of the room is 194 m²

°•° We are to find about the walls

•°• We have to exclude the ceiling and floor portion .

Now ,

☯︎ Area of the ceiling

ㅤㅤ➪ l × b

ㅤㅤ➪ 8 × 6

ㅤㅤ➪ 48 m²

Again ,

☯︎ Area of the floor

ㅤㅤ➪ l × b

ㅤㅤ➪ 8 × 6

ㅤㅤ➪ 48 m²

♧︎︎︎ Adding the areas , we get

ㅤㅤ➪ ceiling + floor

ㅤㅤ➪ ( 48 + 48 ) m²

ㅤㅤ➪ 96 m²

So , we have to decrease the above value from the total area as we are to find the area of the walls .

➪ Total area - ( ceiling + floor ) area

➪ 194 m² - 96 m²

➪ 98 m²

Now , main portion

➪ cost of washing 1 m² = Rs 50 ( given )

➪ cost of washing 98 m² = 50 × 98

ㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤㅤ = 4900

♧︎︎︎ Total cost of washing the room walls

ㅤㅤㅤㅤㅤㅤㅤ➪ Rs 4900

ㅤㅤㅤ꧁ ʙʀᴀɪɴʟʏ×ᴋɪᴋɪ ꧂

ㅤㅤ

Answer 2

➪GIVEN THAT :-

⇨ Length [ L ] = 8m

⇨ Breadth [ B ] = 6m

⇨ Height [ H ] = 3.5m

➪To Find :-.

White washing the four walls of the room at the Rate of ₹50 per m².

[ To Find lateral surface area of the room and multiply the rate ]

➪Solution :-

• Lateral Surface area of a cuboidal room:

⇨ 2H ( L + B)

⇨ 2 × 3.5m .( 8m + 6m )

⇨ 7m × ( 14m )

⇨ 98m²

• Cost for white washing the four walls ;

⇨98m² × Rs 50 per m²

⇨ Rs 480.