20) Suppose ABC Bank sells mortgage-backed securities backed by its $100M portfolio of fixed-rate mortgages with the MBS having the following features: Weighted-average coupon rate = 10% Weighted-average maturity = 360 months Principal = $100M Estimated prepayment speed = 150 PSA Required monthly payment from borrowers = $877,571.57 What is the scheduled principal reduction during the first month?

The Answer is 44238.24 +/- 5000 I would like all the working out, thank you