# The Cost of Preparing the Walls of a Room 12 M Long at the Rate of Rs. 1.35 per Square Metre is Rs. 340.20 and the Cost of Matting the Floor at 85 Paise per Square Metre is Rs. 91.80. - Mathematics

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The cost of preparing the walls of a room 12 m long at the rate of Rs. 1.35 per square metre is Rs. 340.20 and the cost of matting the floor at 85 paise per square metre is Rs. 91.80. Find the height of the room.

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#### Solution

Given that
Length of room = 12m.
Let height of room be ‘h’ m.
Area of 4 walls = 2 (l + b)x h
According to question

⇒2(l+b)xxhxx1.35=340.20

⇒2(12+b)xxhxx1.35=340.20

⇒(12+b)xxh=(170.10)/1.35=126             .......(1)

Also area of floor = l x b
∴lxxbxx0.85=91.80

⇒12xxbxx0.85 = 91.80

⇒b=9m

Substituting b= 9m in equation (1)

⇒(12+9)xxh=126

⇒h=6m

Concept: Surface Area of a Cuboid
Is there an error in this question or solution?

#### APPEARS IN

RD Sharma Mathematics for Class 9
Chapter 18 Surface Areas and Volume of a Cuboid and Cube
Exercise 18.1 | Q 17 | Page 15

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