Answer:
15,539 gallons will remain after 192 days
Explanation:
16,307 - 4x = y
Plug in 192 for x since that's how many days will have passed.
16,307 - 4(192) = y
4 x 192 = 768
Then, subtract 768 from 16,307 to see how many gallons will remain.
16,307 - 768 = 15,539