A 300 gallon tank is full of milk containing 2% butterfat. Milk containing 1% butterfat is pumped in at 10 gallons per minute starting at 10:00 AM and the well-mixed milk is drained off at 15 gallons...

A 300 gallon tank is full of milk containing 2% butterfat. Milk containing 1% butterfat is pumped in at 10 gallons per minute starting at 10:00 AM and the well-mixed milk is drained off at 15 gallons per minute. What is the percent butterfat in the milk in the tank 5 minutes later at 10:05 AM? Hint: How much milk is in the tank at time t? How much butterfat is in the milk at time t = 0?