Joelle has a credit card that has a 19.2% annual interest rate compounded monthly. She owes a total balance of B dollars after m months. Assuming she makes no payments on her account, the table below illustrates the balance she owes after m months. Explain. m B
0 100.00
10 1172.00
19 1352.00
36 1770.80
60 2591.90
69 2990.00
72 3135.80
73 3186.00
Over which interval of time is her average rate of change for the balance on her credit card account the greatest?
1) month 10 to month 60
2) month 19 to month 69
3) month 36 to month 72
4) month 60 to month 73