Your cousin is going to college. Determine the amount to put away.
Determine the present value of an amount of money at various interest rates.
Determine the future value of some money at various interest rates.
Having some money today is equivalent to having some money later.
Given a discount factor, find the discount rate.
How much would you have, and how much money could you borrow today. Then decide if you should borrow from your friend or the bank.
How much can you borrow today?