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.
m
0
10
19
36
60
69
72
73
B
100.00
1172.00
1352.00
1770.80
2591.90
2990,00
3135.80
3186,00
Over which interval of time is her average rate of change for the balance on her credit card amount the greatest?