Answer:
The extra amount to be paid = $ 309.15
Step-by-step explanation:
Credit card bill = $ 7250 .
Interest rate = 16 % .
Monthly payment = $ 657.80
Total amount to be paid in a year = $ 657.80 × 12 = $ 7893.6
Interest amount in 1 year = $ 7893.6 - $ 7250 = $ 643.6.
Monthly payment = $ 455.71.
Total amount to be paid in a 18 months = $ 455.71 × 18 = $ 8202.78
Interest amount to be paid in 18 months = $ 952.78 .
The extra amount to be paid = $ 8202.78 - $ 7893.6 = $ 309.15