The semiannual tuition payment at a major university is expected to be $30,000 for the 4 years

Question:

The semiannual tuition payment at a major university is expected to be $30,000 for the 4 years beginning 18 years from now. What lump sum payment should the university accept now, in lieu of tuition payments beginning 18 years, 6 months from now? Assume that money is worth 7%, compounded semiannually, and that tuition is paid at the end of each half-year for 4 years?