Answer :
Step-by-step explanation:
4/5 gallons for 280 ft² (the ² is missing in the question ...).
3 gallons would be 15/5.
so, what do I need to multiply 4 with to get 15 ?
4×x = 15
x = 15/4
multiplying now also 280 ft² with this factor gives us the answer :
280 × 15/4 = 70 × 15 = 1050 ft²
they can paint 1050 ft² with 3 gallons of paint.