The price of the stock 19 years from now would be the present value of all the dividends to be paid starting year 20. Here, to compute the PV of the dividends, we can use the PV of perpetuity formula as the dividends will be paid for the infinite period of time.
Value of the stock after 19 years = Dividend year 20/ required return
= $20 / 0.0725
= $275.86