Annual salary(2012) = $70,000
Annual inflation = 7%
Therefore, the salary you need to earn in 2020 in order to have the same purchasing power can be calculated below
where
n = 8
r = 7/100 = 0.07
PV = 70, 000
The salary you need to earn in 2020 to have the same purchasing power = $120, 273.03