Q.8 A door of length 2 m and breadth 1 m is fitted in a wall. The length of the wall is 4.5 m and the breadth is 3.6 m (Fig). Find the cost of white washing the wall, if the rate of white washing the wall is ? 20 per\(m^2.\)

Given: Length of wall = 4.5 m
Breadth of the wall = 3.6 m
Length of the door = 2 m
Breadth of the door = 1 m
Area of the wall = l × b = 4.5 m × 3.6 m = 16.20\( m^2 \)
Area of the door = l × b = 2 m × 1 m = 2 \(m^2\)
\(\therefore \) Area of the wall to be white washed = Area of the wall – Area of the door
= 16.20 \(m^2 – 2 m^2= 14.20 m^2\)
Cost of white washing
= Rs. 14.20 × 20 = Rs. 284.00
Hence, the required area = 14.20\( m^2 \)and the required cost = Rs. 284