Five years ago I took out a 30-year fixed $300,000 mortgage with monthly payments and an APR of 8%, compounded monthly. I have made the normal payments in full, and, this morning, after making a normally scheduled payment, I are paying off the balance by taking out a new 30-year fixed mortgage at a lower APR of 6% (with monthly compounding). How much will each monthly payment be?

Please explain step by step