Make sure that the loan is set to $200,000 with the interest rate to 3.5% and also make this a variable rate with 7 years fixed interest, term 30 years. Variable rate ARM loans usually have lower interest rates, but after 7 years - assume the interest rate goes up by .25%

If you pay an extra $350 a month and pay $35,000 additional payment on the 85^th month (or right after 7 years) .. a) how much interest will you save, b) what date will the entire loan get paid , c) how much taxes will you save, d) what is the loan balance on year 18 ? e) how much was the total payment of the entire loan, f) how much was the total interest payment

Ignore part c if that helps