Answer:
Investment in stock C is $122450.3311 rounded off to $122450.33
Explanation:
A portfolio which is equally as risky as market should have a beta equal to the beta of the market as beta is a measure of the riskiness. The beta of market is always equal to 1. The formula for beta of a portfolio is as follows:
Portfolio beta = wA * Beta A + wB * Beta B + ... + wN * Beta N
Where w represents the weight of each stock in the portfolio.
Let investment in stock C be x
1 = 146000/500000 * 0.91 + 134000/500000 * 1.36 + x/500000 * 1.51
1 = 0.26572 + 0.36448 + 1.51x / 500000
1 - 0.6302 = 1.51x / 500000
0.3698 * 500000 = 1.51x
1844900 / 1.51 = x
x = $122450.3311 rounded off to $122450.33