According to the Gordon growth model, if the stock

price is $$50,$ required return on equity is $10\%,$ and the

current dividend is $$3,$ what is the expected growth

rate of dividends?

Suppose the growth rate of dividends is $5\%$ and the

current dividend is $$1.$ If investors are willing to pay

$$21$ for the stock, what must be the required return on

equity?