Laura and Martin obtain a 20-year, $150,000 conventional mortgage at 9.0% on a house selling for $190,000 Their monthly mortgage payment, including principal and interest, is $1350.00. a) Determine the total amount they will pay for their house. b) How much of the cost will be interest? ... a) The total amount that Laura and Martin will pay for their house is $ (Round to the nearest dollar as needed.) b) They will pay a total of $ in interest. (Round to the nearest dollar as needed.)