Based on the Taylor Rule, the formula for calculating the Federal target rate is:
Federal funds rate target = equilibrium real federal funds rate + inflation rate + 1/2(output gap) + 1/2(inflation gap)
We are given that:
equilibrium real federal funds rate = 2%
inflation rate = 10%
output gap = 8%
inflation gap = 10% - 2% = 8%
Substituting to the equation:
Federal funds rate target = 2% + 10% + 0.5*8% + 0.5*8%
Federal funds rate target = 20%