If an amount R is paid at the end of every year for 'n' years, then the net present value of the annuity at an interest rate of i is
R [{(1 + i)n - 1}/ i ]
R [{(1 + i)n - 1}/ i (1 + i)n]
R(1 + i)n
R/(1 + i)n
R [{(1 + i)n - 1}/ i ]
R [{(1 + i)n - 1}/ i (1 + i)n]
R(1 + i)n
R/(1 + i)n