Help mee this is confusing I don't know what to do

Chanelle deposits $7,500 into the bank. she does not withdraw or deposit money for 6 years. she earns 6% interest during that time. what will the balance be when she is finally able to withdraw her money?

Which one ? is the answer and how to find this answer

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?