Help I need help I don’t know how to do this

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?

In the diagram, bc¯¯¯¯¯∥de¯¯¯¯¯ . what is ce ? enter your answer in the box.

4. a single woman uses an online cash flow calculator which reveals a cash flow of 203. what does this mean?