Explanation:
On the client's portfolio (total investment = 120 K + 80 K = 200 K, Â
          = (12.4 %risk premium + 5.4 %risk free return) [tex]\times[/tex] (120 K / 200 K) + 5.4 % [tex]\times[/tex] (80 K / 200 K)
          = 17.8 % [tex]\times[/tex] 0.6 + 5.4 % [tex]\times[/tex] 0.4
          = 12.84 %.
                                 = 22.8 %.