Answer: 1.59375. Round to 1.6 if need be.
Step-by-step explanation:
Their are 384oz in 3 gallons (multiply gallons by 128)
Their are 120 seconds in 2 minutes (multiply minutes by 60)
Multiply 1.5 * 120 = 180 to get how many oz have drained after 2 minutes.
Subtract 384 - 180 = 204 to get how many oz left in the milk container.
Convert 204oz to gallons by dividing by 128. 204 / 128 = 1.59375gallons.