Ana opened a bank account with $1000 that earns interest, compounded continuously, at an annual rate of r=0.02 . Money can be withdrawn from the account at regular intervals, and no additions to the account can be made. The function P models the balance of the account, in dollars, at time t. Assume that Ana withdraws money from the account continuously at a rate of N dollars per year.

Required:
Write down the differential equations that best describes the relationship between P and t?