The balance B (in thousands of dollars) on a car loan satisfies the differential equation dB = 0.1B - R dt where R thousand dollars/year is a constant rate of repayment and t is measured in years. JI (a) (7 pts) If the initial balance is 25 thousand dollars, find the balance at time t. (Your answer may involve R. (b). (3 pts) If the loan is to be paid off after exactly 5 years, solve for the appropriate repayment rate R.