Question

The four walls of a room can be fully covered by 70 square wall papers of 2 m × 2 m size. The length of the room is 18 m and its breadth is twice that of its height. If the cost of carpeting is Rs 20 per square metre, what will be the total expenditure in carpeting the room?

(a) Rs 1800

(b) Rs 5040

(c) Rs 3600

(d) Rs 1400

Answer 1

Correct option is (c) Rs 3600

Let the height of the room be x meters.

∴ Its breadth = 2x meters

∴ Area of the four walls = 2 × x(18 + 2x) = 36x + 4x²

⇒ 36x + 4x² = 2 × 2 × 70

⇒ x² + 9x − 70 = 0

⇒ (x + 14)(x − 5) = 0

⇒ x = 5

Breadth = 2 × 5 = 10m

Area of the floor = 18 × 10 = 180 sq. meter

Cost of paving the floor = 180 × 20 = Rs.3600