Q$2.$ Roland Corporation's stock recently paid a dividend of tf$2\mathrm{.}50$ per share $(Do=tf2\mathrm{.}50.$ The company has a constant growth rate of $5\%$ and a beta equal to $1\mathrm{.}5.$ The rate of return on the market portfolio is $15\%,$ and the risk$-$free rate is $7\%.$

a$)$ Calculate Roland Corporation's discount rate and current stock price $?$

b$)$ Roland is considering a change in policy that will increase its beta coefficient to $1\mathrm{.}75.$ If market conditions remain unchanged, what new constant growth rate will cause the price of Roland stock to remain unchanged?