We need to find the amount of water remaining at t = 2 , 3, and 4.
Water flows at a rate 3/4 gallon per minute.
2nd minute, water goes out by (3/4)*2 = 3/2 gallons
3rd minute, water goes out by (3/4)*3 = 9/4 gallons
4th minute, water goes out by (3/4)*4 = 3 gallons
Remaining volume at t = 2, 3, and 4:
Volume at t = 2 minutes:
Volume at t = 3 minutes:
Volume at t = 4 minutes: