Answer: 0.73
Step-by-step explanation:
Walmart Beta = 0.3616
Amazon's beta = 1.1634
The beta of the portfolio will be a weighted average of the portfolio beta;
= (Walmart beta * Walmart weight) + ( Amazon beta * Amazon weight)
= (0.3616 * 0.54) + ( 1.1634 * (1 - 0.54))
= 0.730428
= 0.73