Suppose you received in your mailbox, a pre-approved credit card application from Coral Bank, offering an introductory interest rate of 12.00 percent per year, compounded monthly for the first 6 months, increasing thereafter to 24 percent per year (months 7 to 12), compounded monthly. Assuming you transferred/borrowed $3000 from this card and made no subsequent payments, how much interest will you owe at the end of the year? (A time-line might help you see the clear picture)

please explain