We have seen before that money deposited into an account with continuous interest follows the A Pert formula However this required strict conditions that the money cannot be withdrawn or added to throughout the term of the investment A more complicated model that allows for deposits withdraws is A t P Kert K where K is the constant amount deposited x o or withdrawn xo each year Problem You just retired to find your retirement savings account has reached 1 000 000 The savings account has a rate of 3 7 compounded continuously Your lifestyle requires you to live off 45 000 each year to be comfortable A How long will your retirement savings account last note your K value should be negative because it is withdrawn from the principal balance Number years ground to the nearest whole number B If at retirement age you are 65 years old how old will you be when the money runs out Number years old round to the nearest dollar