Answer: ER(P) = ERX(WX) + ERY(WY)
16 = 13(1-WY) + 9(WY)
16 = 13 - 13WY + 9WY
16 = 13 - 4WY
4WY = 13-16
4WY = -3
WY = -3/4
WY = -0.75
WX = 1 - WY
WX = 1 - (-0.75)
WX = 1 + 0.75
WX = 1.75
The amount to be invested in stock Y = -0.75 x $106,000
= -$79,500
The Beta of the portfolio could be calculated using the formula:
BP = BX(WX) + BY(WY)
BP = 1.14(1.75) + 0.84(-0.75)
BP = 1.995 - 0.63
BP = 1.365
Explanation: The expected return of the portfolio is equal to expected return of stock X multiplied by the weight of stock X plus the expected return of stock Y multiplied by weight of security Y. The weight of security Y is -0.75. The weight of security X is equal to 1 - weight of security Y. Thus, the weight of security X is 1.75 since the weight of security Y is negative. The amount to be invested in security Y is -0.75 x $106,000, which is equal to -$79,500
The Beta of the portfolio equals Beta of stock X multiplied by weight of stock X plus the Beta of stock Y multiplied by weight of stock Y. The weights of the two stocks have been obtained earlier. Therefore, the Beta of the portfolio is 1.365.