please show reference cells and formulas !

1. As a beginning freshman (Fall 2020), Skipper expects to borrow $12,000 per year in unsubsidized student loans. Assume all loans occur on August 1 of each of his four years in college. Interest accrues at the rate of 5.5% from the time his loan is received, but Skipper does not pay interest while in school. This interest rate applies throughout the term of Skipper's student loan debt. Skipper must begin repaying his loans on August 1, 2024. Assume his repayment term is 10 years. a. What is the balance on Skipper's loan at the time he begins repayment? b. What is Skipper's monthly payment? c. If Skipper wishes to pay off his loan in 5 years, what should he pay each month? 2. Marsha has a credit card with a balance of $16,000. The annual interest rate is 15%. The terms of the credit state that a minimum payment of 4% of the outstanding balance must be paid each month, but no less than $40.00 must be paid each month. Marsha plans to stop using the credit card and pay off the balance according to the terms of the credit. a. How many years will it take to pay off the balance, assuming Marsha only pays the minimum required payment? b. How long will it take to pay off the balance if Marsha pays an extra $40.00 per month? c. How much in addition to the required minimum payments must Marsha pay each month if she wishes to pay off the balance in 4 years