Which is more economical? Breakdown the questions with steps included. Use the PMT formula to determine the regular payment amount, rounded to the nearest dollar. In terms of paying less in interest, which is more economical for a $150,000 mortgage: a 30-year fixed-rate at 8% or a 20-year fixed-rate at 7.5%? How much is saved in interest? (Do not round until the final answer. Then round to the nearest thousand dollars.).