please writedown the complete formula

DCBM, one fund that belongs to Techcombank Wealth Management Company is holding the following portfolio: Stock Beta 0.75 1 Amount invested $300,000 300,000 500,000 500,000 2 3 4 1 1.25 1.45 The risk free rate is 6 percent and the portfolio's required rate of return is 12.5 percent The manager of the fund would like to sell all of its holdings of stock 1 and use that money to purchase more shares of stock 4 to form a new portfolio. al Calculate the beta of the original portfolio (6 points) b/ Calculate the beta of the new portfolio (8 points) c/What is the required return of the new portfolio? (6 points)