12. The length of a room is 3 times its height and breadth is 1 times

1.	12. The length of a room is 3 times its height and breadth is 1 times its height. The cost of whitewashingthe walls at the rate of 1.50 per sq. m is 216. Find the dimensions of the room.
Answer» Let height of room = xThen length of room = 3xbreadth of room = (3/2)x Area of four walls= 2(lengthheight + breadthheight)= 2(3xx + (3/2)xx)= 6x^2 + 3x^2= 9x^2 Cost of white washing = 2169x^2 * 1.5 = 216x^2 = 240/15 = 16x = 4 m Dimensions of room:Length = 3x = 34 = 12 mBreadth = (3/2)x = (3/2)4 = 6 mHeight = x = 4 m

12. The length of a room is 3 times its height and breadth is 1 times its height. The cost of whitewashingthe walls at the rate of 1.50 per sq. m is 216. Find the dimensions of the room.

Answer»

Let height of room = xThen length of room = 3xbreadth of room = (3/2)x

Area of four walls= 2(length*height + breadth*height)= 2(3x*x + (3/2)x*x)= 6x^2 + 3x^2= 9x^2

Cost of white washing = 2169x^2 * 1.5 = 216x^2 = 240/15 = 16x = 4 m

Dimensions of room:Length = 3x = 3*4 = 12 mBreadth = (3/2)x = (3/2)*4 = 6 mHeight = x = 4 m