17. A room is 100m long, 5m broad and 12m high. Find the cost of whitewashing all the four walls, if the cost of whitewashing is Rs.7 per m. What will be the total cost of whitewashing if the ceiling of the room is also white washed.
Answers
Given,
Length = 100m
Breadth = 5m
Height = 12m
Area of wall = 2 ( l + b ) h
= 2 ( 100 + 5 ) 12
= 2(105) 12
= 2520 m²
Area of ceiling = l × b
= 100 × 5
= 500m
Cost of whitewashing = 2520 + 500
= 3020 × 7
= Rs. 21140
Answer:
The total cost of whitewashing is ₹ 21,140.
Step-by-step explanation:
For a room,
length (l) = 100m
breadth (b) = 5m
Height (h) = 12m
Area of whitewashing all the four walls
(surface area of vertical faces of cuboid)
= 2h ( l + b)
= 2 X 12 ( 100 + 5 )
= 24 ( 105 )
= 2520 m²
Ceiling of the room is also white washed.
.: Area of celling = l X b = 100 X 5 = 500 m²
Total whitewashing area
= 2520 + 500
= 3020 m²
cost of whitewashing is Rs.7 per m²
:. cost of whitewashing for room
= 3020 X 7
= ₹ 21,140