My question is: This morning, farmer Rita's workers collected 30,000 gallons of milk and chilled it in a storage tank. They then spent the next 4 hours pumping milk at a rate of 2,880 gallons/hour from the storage tank into a milk tanker. For the next 7 hours, the workers added more milk into the storage tank, at a rate of 1,500 gallons per hour. How many gallons of milk were left in the storage tank? Your thoughts:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
In the first 4 hours, the milk tanker got 4 hours * 2880 gallons / hour = 11,520 gallons. Thus, the storage tank was left with 30,000 gallons - 11,520 gallons = 18,480 gallons. For the next 7 hrs, the workers added 1,500 gallons / hour * 7 hours = 10,500 gallons. The total therefore is 18,480 gallons + 10,500 gallons = 28,980 gallons. The final answer: 28980.