The value of some good wine increases with age. Thus, if you are a wine dealer, you have the problem of deciding whether to sell your wine now, at a price of $P a bottle, or to sell it later at a higher price. Suppose you know that the amount a wine-drinker is willing to pay for a bottle of this wine t years from now is $P(1 + 20√t). Assuming continuous compounding and a prevailing interest rate of 5% per year, when is the best time to sell your wine?