Question

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

Answer 1

Question

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

Given,

Dimensions of bedroom =8 m×7 m×5 m

Area of room = area of cuboid =2(lb+bh+hl)

=2(8×7+7×5+5×8)

=2(56+35+40)

=2(131)

=262 m

2

Hence, area of room =262 m

2

Area of window = Area of rectangle =l×b

=2×1=2 m

2

There are 2 windows, total area =2×2=4 m

2

Area of door =l×b=3×1=3 m

2

∴ Area of whitewashing room = Area of room − [area of door + area of window]

=262−[4+3]

=262−7

=255 m

2

Hence, the cost of whitewashing (at Rs. 50 per square meter ) =255×50

=Rs. 12750

Hence, the cost of whitewashing the room is Rs. 12750.