Question

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

• A. $Rs.1800$
• B. $Rs.5040$
• C. $Rs.3600$
• D. $Rs.1400$

Answer 1

The correct option is C $Rs.3600$

Let the height of the room be $x$ meters.
$\therefore$ its breadth $=2x$ meters
$\therefore$ Area of the four walls $=2\times x(18+2x)=36x+4x^2$
$\Rightarrow 36x+4x^2=2\times 2\times 70$
$\Rightarrow x^2+9x-70=0$
$\Rightarrow (x+14)(x-5)=0$
$\Rightarrow x=5$
Breadth $=2\times 5=10m$
Area of the floor $=18\times 10=180$ sq.meter
Cost of paving the floor $=180\times 20=Rs.3600$