Answer:
-0.5
Explanation:
Stock Investment (W) Beta (B) W*B
A 200,000 1.50 300,000
B 300,000 X 300,000X
C 500,000 1.20 600,00
1,000,000 900,000+300,000X
<em>Using the formula of Beta of Portfolio to find out X
</em>
0.75 = 900,000 + 300,000X / 1,000,000
0.75 * 1,000,000 = 900,000 + 300,000X
750,000 = 900,000 + 300,000X
750,000 - 900,000 = 300,000X
-150,000 = 300,000X
X = -150,000 / 300,000
X = -0.5
So, the beta of stock B is -0.5.