Answer:
1400 ft2
Step-by-step explanation:
if 280 ft2 comes from 4/5 of 1 gallon of paint, then do 280 x 4, because their are 4 gallons of paint. after you x that it will be 1120 ft2. but the extra 1/5 paint from all 4 of the gallons comes out to 4/5 so add 280 ft2 to that 1120 ft2.
it comes out to 1400 ft2.
