Inflation the impact of inflation on a 20000 pension can be

Question

Question: Inflation the impact of inflation on a $20,000 pension can be measured by the purchasing power P of $20,000 after t years. For an inflation rate of 5% per year, compounded annually, P is given by

P = 20,000e^20.0495t

At what rate is purchasing power changing when t = 10? (Source: Viewpoints, VALIC)