Answer:
See Explanation
Step-by-step explanation:
The gallon sizes and prices are given below:

Answer:
Im answering so i wont lose this convo... lol
The points have to have the coordinate y=4 to be on the y=4 line
only the (1, 4) point matches this, so yes it is a solution, all others not and are therefore no
it would obviously take 15 days if this answers your question