Answer:
New portfolio return = 11.2%
New portfolio beta = 1.23
Explanation:
The total valuw of investment in new portfolio will be = 90000 + 1000*10 = $100000
The weight of Alpha stock in new portfolio will be = 10000 / 100000 = 0.1 or 10%.
The expected return of the new portfolio will be,
Return of Portfolio = 9/10 * 0.11 + 1/10 * 0.13 = 0.112 or 11.2%
The new portfolio beta will be,
Portfolio beta = 9/10 * 1.2 + 1/10 * 1.5 = 1.23