Joe's dad is only , but he's already thinking about retiring. If he retires early at age , he will receive an annual pension starting at and increasing at a rate of each year to account for inflation. If he waits until he is , his pension will be a larger percentage of his salary at that time. He figures that it will be about to start and the same increase after that for inflation. He wants to know which plan will pay out the largest total by age . Show him how to find out the answer to his question.