What is the present value of of the following cash flows at an interest rate of 10% per year?

a. $100 received 5 years from now?

b. $100 received 60 years from now?

c. $100 received each year beginning one year from now and ending 10 years from now?

d. $100 received each year for 10 years beginning now?

e. $100 each year beginning one year from now and continuing forever (no need financial keys, just common sense)