A lottery prize gives the winner a choice between (1) $10,000 now and another $10,000 in 5

Question:

A lottery prize gives the winner a choice between (1) $10,000 now and another $10,000 in 5 years, or (2) four $6700 payments—now and in 5, 10, and 15 years.
a. Which alternative should the winner choose if money can earn 6% compounded annually? In current dollars, what is the economic advantage of the preferred alternative?
b. Whichalternativeshouldthewinnerchooseifmoneycanearn8.5% compounded annually? In current dollars, what is the economic advantage of the preferred alternative?