I need help in this question. Please I have only 40 minutes. Please do it correctly and 100% and post complete and correct solution

Five years ago, Mr. Moneypenny purchased a rare coin for $1,000. Today he sold the coin for $6,000. If the annual inflation rate for the past 5 years has been at 4%, state here on Blackboard the after-tax real percent interest rate (in percent to 2 decimal places, like 9.38%) for this investment. Assume the net capital gains tax rate is 15%