Question

the dimension of mr narula's bedroom is 8m × 7m × 5m. it has two windows each measuring 2 m × 1m and one door measuring 3m × 1m. find the cost of white washing the room ₹50 per square metre.​

Answer 1

Answer:

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.