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Question
The cost of papering the four walls of a room at Rs 1 per m2 is Rs. 210. The height of the room is 5 m. Find the length and the breadth of the room if they are in the ratio 5:2.
Solution
∵ The cost of papering the four walls of the room at Rs. 1per m2 is Rs.210.
∴ The area of the 4 walls is 210m2,
The length and breadth are in the ratio 5 : 2 ...(given)
Let the common multiple be x
∴ Length = 5x m
breadth = 2x m
height = 5m ...(given)
Surface area of the 4 walls = 2hl + 2hb
210 = 2 x 5 x 5x + 2 x 5 x 2x
210 = 50x + 20x
210 = 70x
∴ x = `(210)/(70)`
∴ x = 3
length = 5x = 5 x 3 = 15cm
beadth = 2x = 2 x 3 = 6cm.
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