A tank is used to mix sugar solutions for use in making candies at a factory. The tank initially holds 60 gallons of
pure water. Two pipes that flow into the tank and a third pipe that flows out of the tank are opened. The first
pipe has a solution of 0.5 pounds of sugar per gallon and flows into the tank at a rate of 7 gallons per minute.
The second pipe has a solution of 1.5 pounds of sugar per gallon and flows into the tank at a rate of 4 gallons per
minute. The tank is well-stirred. The mixture leaves the tank at a rate of 12 gallons per minute. Write an
Initial-Value Problem that models the amount of sugar in the tank (in pounds) at any time . You do not need
to solve the problem.