Answer:
60%
Explanation:
Since the question suggests a combined expected return portfolio of 12.8%, we ignore the standard deviation for both of the securities.
The percentage of the portfolio will consist of security A, Wa =
(Combined portfolio expected return - expected return of security B) / (expected return of security A - expected return of security B)
Wa = (0.128 - 0.11) / (0.14 - 0.11)
Wa = 0.018/0.03
Wa = 0.60 = 60%