The cost of preparing the walls of room 12m 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.

Explanation

Area of the floor = Cost of matting/rate per m^2=`'( 91.80/0.85 )m^2'` =`'108m^2'`
∴ Breadth of the room = Area of floor/length='`(108/12)m=9m'`
Area of four walls of the room =
Cost of preparing the walls/Rate per `m^2='340.20/1.35 m^2=252 m^2'`
Also, of four walls=`2(Length +Breadth)×Height'`=`'2(12+9)'×height`
∴`'(12+9)×height=252'⇒'h=6 m'`