Upon receiving terms of contract A, your customer realizes that monthly payment of XA (calculated above) is beyond her earning power in year 1, 2 and 3, but it will be well within her means from year 4 onwards. You then decide to offer her the following alternative: Contract B: a 15-year fixed rate loan with a variable payment schedule, with a monthly payment of XA, in the first three years (36 months), and a monthly payment of Xg for the remaining 12 years. Calculator in excel the value of X and create a modified version of amortization table for contract B