If the length of the room is 10 m, then what is the height of the room?
I. The cost of painting the walls of the room at the rate of Rs. 25 per sq metre is Rs. 6,400.
II. The cost of carpeting the floor at the rate of Rs. 140 per sq metre is Rs. 8,400.
Let breadth and height of the room be b and h respectively. From I, Area of the four walls of the room = 2(10 + b)h = 6400/25 ⇒ 2(10 + b)h = 256 ⇒ (10 + b)h = 128 m……… (i) From II, 10 × b = 8400/140 ⇒ b = 8400/(140 ×10) = 6 m………(ii) By putting the value of b in equation (i), we get (10 + 6)h = 128 m ⇒ h = 128/16 = 8m. Therefore, both statement I and statement II together is required to answer the question.