you plan to start saving for your son's college education. He will begin collage when he turns 18 years old and will need $4,000 at that time and in each of the following three years. You will make a deposit at the end of this year in an account that pays 6% compounded annually as well as an identical deposit at the end of each year, with the last deposit occurring when he turns 18. If an annual deposit of $1,484 will allow you to reach your goal, how old is your son now?

Please explain the answer.