Find an Expression for the Present Discounted Value of

Essay

Find an expression for the present discounted value of
(A)$500 to be paid at the end of five years.
(B)$100 to be paid at the end of two years and $100 to be paid at the end of three years.
(C)$8 to be paid at the end of one year,$8 to be paid at the end of two years,and $80 to be paid at the end of three years.