Question 761491
Surface Area:
2 x 15ft x 5ft = 150ft^2
2 x 30ft x 5ft = 300ft^2
   30ft x 15ft = 450ft^2
          Total = 900ft^2
You will require to buy 4 gallons of paint
giving you cover for 1000ft^2.
Volume:
15ft * 30ft * 5ft = 2250ft^3
2250 * 7.48 = 16,830 gallons.
Hope this helps.
:-)