Question

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. Find the cost of whitewashing the wall, if the rate of whitewashing the wall is Rs. 20 per $m^2$.

Answer 1

Given, a wall with dimensions = 4.5 m x 3.6 m
And a door with dimensions = 2 m x 1 m
Area of rectangular door = $length\times breadth$
= $2m\times 1m=2m^2$
Area of wall including door = $length\times breadth$
= $4.5m\times 3.6m=16.2m^2$
Now, Area of wall excluding door
= Area of the wall including door - Area of door
$=16.2-2=14.2m^2$
Since, the cost of whitewashing 1 $m^2$ of wall = Rs. 20
Therefore, the cost of whitewashing 14.2 $m^2$ wall
= Rate of whitewashing x Area to be whitewashed
= 20 x 14.2 = Rs. 284
Thus, the cost of whitewashing the wall excluding the door is Rs. 284