1. Assuming the cost of mortgage is $400,000, and the owner of the house makes a down payment of $40,000, with 8% interest rate and 10 years repayment plan. a. calculate the total amount of loan, monthly rate, number of payment periods, monthly payment, total interest paid, and amount borrowed. b. With the aid of what PMT function in a one variable condition, calculate monthly payment, total amount payable, total interest payable for: 12 yrs, 16yrs,20yrs,25 yrs, 30 yrs, 35 yrs mortgage