Question

The dimensions of a hall are 20m×15m×8m. Find the cost of white washing it's walls and ceiling at the rate of rupees 20per 10m^2. Also find the volume of air present in the hall
The answer is 1360 and 2400m^3
But I need to know the explanation
I will mark u as brainlest if u answer these question

Answer 1

Answer:

Step-by-step explanation:

Area of wall = lh + lh + bh + bh = 2lh + 2bh = 2h *(l + b)

Area of ceiling = lb

Area of wall and ceiling = 2h(l +b) + lb

=  2*8* (20 +15) + 20*15 = 16*35 + 20*15

= 560 + 300 = 860

Cost of painting per m^2 =20/10 = 2

Cost of painting 860 m^2 = 860 * 2 =  1720

Volume = l * b *h = 20 * 15 * 8 = 2400 m^3