Question

The cost of plastering the four walls of a room is RS 25 The cost of plastering a room twice in length breadth and height will be

• A. Rs 50
• B. Rs 75
• C. Rs 100
• D. Rs 200

Answer 1

The correct option is C Rs 100

Let the length ,breadth and height is l , b and h respectively

Then area of four wall of room =2h(l+b) sq m

If length breath and height is twice. Then length=2l breadth ,=2b and height =2h

Then area of new room wall=$2\times 2h(2l+2b)=8h(l+b)$ sq m

But cost of plastering the four walls Rs 25

Then cost of plastering the four walls of new room=$\frac{8h(l+b)\times 25}{2h(l+b)}=100$ Rs