Question

The dimension of Mr Narula's bedroom is $8$ $m\times$ $7m\times$ $5$ $m$ . It has two windows,each measuring $2$ $m\times 1m$ and one door measuring $3$ $m\times 1m.$ Find the cost of white washing the room at $50Rs.$ per square metre.

Answer 1

Area of cuboid$=2(lb+bh+lh)$

Area of room $=2(8\times 7+7\times 5+5\times 8)$

Area of room$=2(56+35+40)$

Area of room$=2\times 131=262m^2$

Area of window$=(2\times 1\times 2)m^2=4m^2$

Area of door$=(3\times 1)m^2=3m^2$

Area of white washing$=(262-7)m=255m$

Cost of white washing$=Rs(255\times 50)=Rs12750$