A 50 gallon tank is filled with a solution that contains 10 pounds of salt. Fresh water is pumped into the tank at a rate of 5 gallons per minute. The well-stirred mixture is pumped out at the same rate.

A) Find Q(t) for the amount of salt in the tank after t minutes.

B) Find the amount of salt in the tank after 2 minutes.

C) Find the limit of Q(t) as t approaches infinity. Interpret the result.