Question

A door of length $2m$ and breadth $1m$ is fitted in a wall. The length of the wall is $4.5m$ and the breadth is $3.6m$. Find the cost of white washing the wall is $Rs.20$ per $m^2$.

Answer 1

The wall will be whitewashed but the door will be left out.
Hence the area whitewashed $=$ area of wall $-$ area of door.
Area of wall $=$ length of wall $\times$ breadth of wall $=4.5\times 3.6=16.2$ m. sq.
Area of door $=$ length of door $\times$ breadth of door $=2\times 1=2$ m. sq.
Hence area to be whitewashed $=16.2-2=14.2$ m. sq.
Cost of white washing $=Rs.20$ m. sq.
Total cost of whitewashing $=20\times 14.2=Rs.284$