More on credit cards: This is a continuation . Suppose again that you make a charge of $1000 to a new credit card but then make no other charges. Assume that the finance charges amount to a monthly...

More on credit cards: This is a continuation . Suppose again that you make a charge of $1000 to a new credit card but then make no other charges. Assume that the finance charges amount to a monthly rate of r as a decimal. Let the minimum payment as a percentage of the new balance be given by the number m when expressed as a decimal. Then your balance B, in dollars, is an exponential function of the number of payments n, with initial value $1000 and base

a. Find the exact value of the base a if the monthly finance charge is 1.5% and the minimum payment is 4% of the new balance.

 b. In the situation of part a, by what percentage does your balance decrease each month?

c. What is the exact value of the base a if the monthly finance charge is 1.5% and the minimum payment is 1% of the new balance? Is this a realistic situation?