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

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