Answer:
V = 10 + 4t
Step-by-step explanation:
Your V is your total volume. That's what you are looking for. V changes depending on t, the amount of minutes passed.
You have a constant variable given: 4 gallons per minute (t). You can express this with "4t" (4 × t).
You begin with 10 gallons and add the above.
This results in 10+4t = V at any given time.