having trouble.. first attempt. no idea how to start this question

DeWitt Company sells a kitchen set for $495. To promote July 4, DeWitt ran the following advertisement: Beginning each hour up to 4 hours we will mark down the kitchen set 11%. At the end of each hour, we will mark up the set 2%. Assume Ingrid Swenson buys the set 1 hour 50 minutes into the sale. a. What will Ingrid pay? (Round your answer to the nearest cent.) x Answer is complete but not entirely correct. Ingrid pays $ 449.40 x b. What is the markdown percent? (Round your answer to the nearest hundredth percent.) x Answer is complete but not entirely correct. Markdown percent 91.00 x%