Question

The dimensions of a room are 12.5 m by 9 m by 7 m. There are 2 doors and 4 windows in the room; each door measures 2.5 m by 1.2 m and each window 1.5 m by 1 m. Find the cost of painting the walls at Rs 3.50 per square metre.

Answer 1

Dimensions of a room
=$12.5m\times 9m\times 7m$
$\therefore$ Total surface area of the walls
= $2(l+b)\times h=2(12.5+9)\times 7m^2$
= $2\times 21.5\times 7=301.0m^2$
Area of 2 doors = $2\times (2.5\times 1.2)m^2$
= $2\times 3.00=6m^2$
Area of 4 windows = $4\times (1.5\times 1)m^2$
= $4\times 1.5=6m^2$
$\therefore$ Remaining area of the walls
= 301 - ( 6 + 6) $m^2$
= 301 - 12 = 289 $m^2$
Rate of painting the walls = Rs. 3.50 per $m^2$
$\therefore$ Total cost = Rs. 3.50
$\therefore$ Total surface area of the walls
= $2(l+b)\times h=2(12.5+9)\times 7m^2$
= $2\times 21.5\times 7=301.0m^2$
Area of 2 doors = $2\times (2.5\times 1.2)m^2$
= $2\times 3.00=6m^2$
Area of 4 windows = $4\times (1.5\times 1)m^2$
$4\times 1.5=6m^2$
$\therefore$ Reamining area of the walls
= $301-(6+6)m^2$
= $301-12=289m^2$
Rate of painting the walls = Rs. 3.50 per $m^2$
$\therefore$ Total cost = Rs. 3.50 $\times$ 289 = Rs. 1011.50