Question

The internal measures of a cuboidal room are:- 12×8×4 metres. Find the total cost of whitewashing all the 4 walls if the cost is rs. 5 per square metres. What will be the cost of whitewashing if the sealing of the rooms are also whitewashed. ​

Answer 1

$\sf{\huge{\underline{\pink{Given :-}}}}$

• The internal measures of a cuboidal room are 12×8×4 metres.

• The cost of whitewashing all the 4 walls if the cost is rs. 5 per square metres.

• The cost of whitewashing of the ceiling of the rooms are also white washed.

$\sf{\huge{\underline{\purple{To\:Find :-}}}}$

• The total cost of whitewashing all the 4 walls & white washing the ceiling.

$\sf{\huge{\underline{\green{Solution :-}}}}$

We have ,

• The length of cuboidal room 12 m.

• The breadth of cuboidal room 8 m.

• The height of cuboidal room 4 m.

The Area of Four walls = CSA of Cuboid

➝ 2 × ( l + b ) × h

➝ 2 × ( 12 + 8 ) × 4

➝ 2 × 20 × 4

➝ 8 × 20

➝ 160 m²

Cost of whitewashing all the 4 walls = 5 × 160

➝ Rs . 800

The area of ceiling = l × b

➝ 12 × 8

➝ 96 m²

The cost of whitewashing of the ceiling = 96 × 5

➝ Rs.480

Total cost = 480 + 800

➝ Rs.1280

The total cost of whitewashing all the 4 walls & white washing the ceiling Rs.1280 .