Question

the internal measures of a cuboidal room are 12m×9m×6m. find the total cost of whitewashing all four walls of a room, if the cost of whitewashing is rs. 5 per m². what will be the cost of white washing if the ceiling of room is also white washed?​

Answer 1

Answer:

₹ 1800

Step-by-step explanation:

Given:-

Length $(l)$ = 12 m

Breadth $(b)$ = 9 m

Height $(h)$ = 6 m

Cost of whitewashing per $m^{2}$ = ₹ 5

To find:-

Cost of white washing including the ceiling of room.

Solution:-

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

⇒ $2$ × $6$ × $(12+9)$

⇒ $2$ × $6$ × $21$

⇒ $12$ × $21$

⇒ $252 m^2$

Area of the ceiling = $l$ × $b$

⇒ $12$ × $9$

⇒ $108 m^2$

Area of the cuboidal room excluding the floor = $252m^{2}+108m^{2}$

⇒ $360m^{2}$

Cost of whitewashing per $m^{2}$ = ₹ 5 (∵ Given)

Cost of white washing including the ceiling of room = Area of the cuboidal room excluding the floor × Cost of whitewashing per $m^{2}$

⇒ $360$ × $5$

⇒ ₹ 1800

∴ The cost of white washing including the ceiling of room is ₹ 1800.