I'm being told I'm missing a few steps and keep getting this wrong. Can you please walk me through the process? Thank you.

The purchasing power P (in dollars) of an annual amount of A dollars after t years of 3.1% inflation (the rate of inflation for November 2023, according to the U.S. Labor Department) decays according to the following formula: P = Ae^-0.031t How long will it be before a retirement pension of $90,000 per year has a purchasing power of $20,000? (Round your answer to two decimal places.)

In a couple sentences on what this means to you without using the phrase "purchasing power."