(3 points) Mr. Smith is purchasing a $180000 house. The down payment is 20 % of the price of the house. He is given the choice of two mortgages: a) a 30-year mortgage at a rate of 7 %. Find the monthly payment: $ (ii) the total amount of interest paid: $ b) a 15-year mortgage at a rate of 7 %. Find The monthly payment: $ (Ithe total amount of interest paid: $ Md