We will assume that the total of the trip is paid with the credit card. Recall that the amount after t years, when the rate is compounded continously would be
where P is the principal, r is the rate and t is the amount of years.
In this case, we have r=38.99%, t =1 and P=5500. So we have that the amount of debt after one year would be
so after one year, the debt would be 8122.58