Do this in excel

P$13-11$ ROE and recapitalization At the beginning of the year you invest $$40,000$ of your own money plus $$40,000$ that you borrowed at $6\%$ interest to purchase $$80,000$ worth of GoFast stock, which earns a return of $13\%.$ You pay taxes on the money you make on the stock at the rate of $28\%,$ but you can deduct the interest you pay on your loan from your stock income before calculating your tax bill.

a$.$ Calculate your net after$-$tax return on these positions.

b$.$ What would your after$-$tax return have been if you had never borrowed money and had invested just $$40,000$ in GoFast stock?