Question

The dimensions of a room are $9m\times 8m\times 6.5m.$ It has one door of dimensions $2m\times 1.5m$ and two windows each of dimensions $1.5m\times 1m.$ Find the cost of whitewashing the walls at $Rs.6.40$ per $m^2$.

Answer 1

The dimensions of a room are $9m\times 8m\times 6.5m.$

dimensions of one door $2m\times 1.5m$

dimensions of window $1.5m\times 1m.$

Area of foul walls $=2h(l+b)$

$=2\times 6.5(9+8)=221m^2$

Area that is to be white washed $=$ Area of four walls $-$ (Area of $1$ door $+$ Area of $2$ windows)

$=221-(2\times 1.5)-2(1.5\times 1)=215m^2$

Cost of White Washing the wall @ $Rs.6.40$ per $m^2$ $=215\times 6.40=Rs.1376$