How am I to use Excel to help me answer and present these answers?

1. Maria and Tony are high income earners in their mid-30s. Their marginal tax rate (mtr) is 24%. They have a $100,000 debt which has an interest rate of 8% pa, but have also managed to save $100,000 in a bank account. They have come to you because you are a well-known expert financial adviser. Explain to them why they should repay their loan as a priority. In doing do so, explain to them the concept of notional return, and let them know what their notional return would be on repayment of the loan.
2. Maria and Tony have come back to you after a year and have managed to save another $50,000 from their (high) incomes. They have a 20-year plan to increase their wealth for retirement. Based on the information in Lesson 6.1 A and B, what would you advise them to do with the $50,000? And why? Include some modeling using the compound interest formula.