tak questions with answers but i dont know how to find the answer. What is the formula??

You take out a 40 month car loan at 5%. The monthly payments at the end of each month are $400. How much will the loan company have earned by the end of the loan period? $17,371

You are saving up money for graduate school. Your bank is only paying 2% interest. How much money will you have saved in 2020 (5 years from now) if you put $4,000 into the bank each year? $20,816

You take out a 40 month car loan at 5%. The monthly payments at the end of each month are $400. How much will the loan company have earned by the end of the loan period? $17,371 You are saving up money for graduate school. Your bank is only paying 2% interest. How much money will you have saved in 2020 ( 5 years from now) if you put $4,000 into the bank each year? $20,816