How to get the answer 1.15

What is the optimal portfolio weight for Amazon.com Inc. (ticker: AMZN)?

The top 5 stocks in the S&P 500 index, when ranked by market capitalization, make up 22% of the total market capitalization of the S&P 500 index. Numerical estimates of the mean (or expected) rates of return values of these top five stocks, expressed in decimal (not percentage) form, are listed in the table below. STOCK TICKER MEAN RETURN Apple, Inc. AAPL 0.69 Amazon.com Inc. AMZN 0.65 Microsoft Corp. MSFT 0.44 Alphabet, Inc. GOOG 0.36 Facebook, Inc. FB 5.41 The variance of returns (entries on the main diagonal) and covariances between returns of these top five stocks, expressed in decimal (not percentage) form, are as follows: AAPL AMZN MSFT GOOG FB AAPL 0.21 0.12 0.17 0.13 0.16 AMZN 0.12 0.15 0.12 0.10 0.12 MSFT 0.17 0.12 0.19 0.14 0.15 GOOG 0.13 0.10 0.14 0.15 0.14 FB 0.16 0.12 0.15 0.14 0.21 Assuming there is a risk-free asset available in addition to these 5 risky assets, determine the portfolio weightings for each of these stocks of the unique fund Fas defined in the One-fund theorem of Modern Portfolio Theory. Note that short positions (negative weights) are permissible and the sum of all the weights must be equal to one. The annual risk-free rate is 10%. What is the optimal portfolio weight for Amazon.com Inc. (ticker: AMZN)? Please express your answer in decimal (not percentage) form and round your numerical answer to two decimal places