Question

the internal measure of cuboidal room are 12 metre × 8 metre × 4 metre find the total cost of while visiting all four walls of a room ,if the cost of whitewashing is rupees 5 per metre what will be the cost of white washing if the ceiling of the room is also white washed

Answer 1

Lateral surface area of room = 2h (l+b)
=2×4 (12+8)
=8×20
=160 m
Total cost of four wall which is white washed = 160×5=800 rupees
If the ceiling is also white washed then area of ceiling = l×b
=12×8
=96
Cost of ceiling for white washed = 96×5
=480 rupees
Overall cost of four wall including ceiling = 800+480=1280 rupees

Answer 2

Lsa of the room=2h(l+b)
=2*4m*20m
=160m sq
Cost of white washing =160m sq*Rs 5/m sq
=Rs 800
Cost of white washing if ceiling is also included
=Rs 800 + 8m*12m*Rs 5/m sq
Rs(800+480)= Rs 1280
I hope it may help you ☺️☺️