An elderly lady owns a home for which she had completely paid. She arranges a reverse mortgage for $100,000 whereby she will receive monthly payments for the home form a bank. She will be allowed to live in the house until her death, whereupon her estate will receive the equivalent of the remaining payments in a lump sum. The bank then owns the home. One month after she turns 70, she begins receiving monthly payments on a 30-year reverse mortgage at 7% interest compounded monthly. I've calculated the (correct) answer of her receiving 665.30$ a month but I am trying to figure out what lump sum payment will be made to the estate if she dies at age 80. The answer is (85,812$) but I am having trouble getting this. Any help would be appreciated