1. The problem statement, all variables and given/known data A health club is opened, the fraction of members still enrolled t months from their initial visit is given by the function f(t)= e-t/20. the club initially accepts 300 members and will accept new members at a rate of 10 per month. How many people will be enrolled 15 months from now. 2. Relevant equations N/A 3. The attempt at a solution I remember my professor referencing this problem could be done as a differential equation problem instead of a survival/renewal problem (which I can do). Following the idea of inflow-outflow, I came up with dP/dt= 10 (inflow) - ? with P being members I'm not sure how to take the fraction of people and make that into a rate. Once I figure that out I could likely solve the differential normally for P.