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

Length of room (l) = 12.5 m

Breadth (b) = 9 m

and height (h) = 7 m

$\therefore \text{Total area of walls}=2h(l+b)$

$=2\times 7[12.5+9]=14\times 21.5m^2$

$=301m^2$

$\text{Area of 2 doors of}2.5m\times 1.2m$

$=2\times 2.5\times 1.2m^2=6m^2$

$\text{and area of 4 window of}1.5m\times 1m$

$=4\times 1.5\times 1=6m^2$

$\therefore \text{Remaining area of walls}=301-(6+6)$

$=301-12=289m^2$

$\text{Rate of painting the walls}=Rs3.50per{m}^2$

$\therefore \text{Total cost}=289\times 3.50=Rs1011.50$