A 100-L tank is filled with pure water when an inflow pipe is opened and a sugar solution with a concentration of 20 gm/L flows into the tank at a rate of 0.5 L/min. The solution is thoroughly mixed and flows out of the tank at a rate of 0.5 L/min.
a. Find the mass of sugar in the tank at all times after the inflow pipe is opened.
b. What is the steady-state mass of sugar in the tank?
c. At what time does the mass of sugar reach 95% of its steady state level?