Your university advertises that next year's "discounted tuition is $18,000 and can be paid in full by July 1. The other option is to pay the first semester's tuition of $9,500 by July 1, with the remaining $9,500 due of January 1. Assuming you (or your parents) have $18,000 available for the full year's tuition, which tuition plan is more economical if you (or your parents) can earn 6% annually on a six-month CD