Question

The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and ceiling at the rate of Rs 7.50 per m^2.​ ?​

Answer 1

$\rm{\underline{Given:-}}$

• Length (l) of room = 5 m

• Breadth (b) of room = 4 m

• Height (h) of room = 3 m

$\bf \large\underline{Solution:-}$

• It can be observed that four walls and the ceiling of the room are to be white washed.

• Total area to be white washed = Area of walls + Area of ceiling of room

$\large{\rm{= 2lh+2bh+lb}}$

$\large{\rm{=2×5×3+2×4×3+5×4}}$

$\large{\rm{=30+24+20}}$

$\large{\rm{=74}}$

$\sf{Area = 74\:m²}$

• Also,

Cost of white washed per m² area = Rs. 7.50 (given)

Cost of white washed 74 m² = Rs. (74×7.50)

• $\bf \large\underline{Rs\:555 }$

Answer 2

Answer:

Length (l) of room = 5 m

• Breadth (b) of room = 4 m

• Height (h) of room = 3 m

\bf \large\underline{Solution:-}

Solution:−

It can be observed that four walls and the ceiling of the room are to be white washed.

Total area to be white washed = Area of walls + Area of ceiling of room

\large{\rm{= 2lh+2bh+lb}}=2lh+2bh+lb

\large{\rm{=2×5×3+2×4×3+5×4}}=2×5×3+2×4×3+5×4

\large{\rm{=30+24+20}}=30+24+20

\large{\rm{=74}}=74

\sf{Area = 74\:m²}Area=74m²

Also,

Cost of white washed per m² area = Rs. 7.50 (given)

Cost of white washed 74 m² = Rs. (74×7.50)

\bf \large\underline{Rs\:555 }

Rs555