Answer:
The proportion of the investment is 100%.
Explanation:
This can be calculated using the following formula:
Rportfolio = (y * Rrisky) + ((1 - y) * Ttbill) ..................... (1)
Where;
Rportfolio = Overall portfolio expected rate of return = 15%. or 0.15
Rrisky = risky portfolio expected rate of return = 15%, or 0.15
Ttbill = T-bill rate = 10%, or 0.10
Substituting the values into equation (1) and solve for y, we have:
0.15 = (y * 0.15) + ((1 - y) * 0.10)
0.15 = 0.15y + 0.10(1 - y)
0.15 = 0.15y + 0.10 - 0.10y
0.15 - 0.10 = 0.15y - 0.10y
0.05 = 0.05y
y = 0.05 / 0.05
y = 1.00, or 100%
Therefore, the proportion of the investment is 100%.