take it by steps do it year by year for example i had a problem like this today alright lets say you had 1,000 dollars in the bank ok now one year at a time...so you start off with 25 percent intrest every year for four years you would end up with 1,025 dollars at the end of the first year and it countinues until you hit the fourth year same with this question..just start with 595 then add 5.5 percent of intrest every year for 4 years and you will get the answer.