please show work

Answer both parts of this question. a. If you invest $1200 a year at the end of each year for the next twenty-four years in a broadly-based stock market fund which historically has earned 7.5% per year, how much will you expect have at the end of these 24 years if you believe stock market history is an excellent guide to the future? b. If instead you invest $1150 a year at the beginning of each year for the next twenty-four years in the same fund, how much would you have at the end of those twenty-four years