Yuki9
So according to the problem, we have: length = 15m breadth = 10m height = 4m
We already know that in order to find the total area of a cuboid (the room is a cuboid), we use the relation: lb + bh + lh + lb + bh + lh which can be simplified to: 2lb + 2bh + 2lh = 2(lb + bh +lh) where 2lb is the area of the roof floor, 2bh is the area of the narrower walls, 2lh us the area of the broader walls.
But in the problem, we have been asked to first find the 'lateral surface area' and not the total surface area, which is basically the total surface area without the area of the roof and floor. So we can simplify the relation to: 2bh + 2lh = 2h(l + b)
So the lateral surface area of the room is: 2x4m(15m + 10m) = 8m(25m) = 8m x 25m = 200sq. m
Since the cost of painting 1sq.m = Rs. 50/- Therefore, the cost of painting 200sq. m = Rs. (200 x 50)/- = Rs. 10000/-
Answers & Comments
length = 15m
breadth = 10m
height = 4m
We already know that in order to find the total area of a cuboid (the room is a cuboid), we use the relation:
lb + bh + lh + lb + bh + lh
which can be simplified to:
2lb + 2bh + 2lh = 2(lb + bh +lh)
where 2lb is the area of the roof floor, 2bh is the area of the narrower walls, 2lh us the area of the broader walls.
But in the problem, we have been asked to first find the 'lateral surface area' and not the total surface area, which is basically the total surface area without the area of the roof and floor.
So we can simplify the relation to:
2bh + 2lh = 2h(l + b)
So the lateral surface area of the room is:
2x4m(15m + 10m) = 8m(25m) = 8m x 25m = 200sq. m
Since the cost of painting 1sq.m = Rs. 50/-
Therefore, the cost of painting 200sq. m = Rs. (200 x 50)/- = Rs. 10000/-
Hope this helps!