A person who works from the age of 25 to 65 expects to have an annual pension of $35,000 upon retirement. If life expectancy is 90 years, how much money must he contribute monthly for his pension during his working life? (Discount rate 7%) Calculate is the savings goal at retirement and calculate the required monthly savings and estimate how it would change in the face of a decrease in the discount rate from 7% to 4%