Where is this 0.5 come from? How can I find 0.5? Thank you!

9. Portfolios with more than one asset: Jackie is analysing a two-share portfolio that consists of a Utility share and a Commodity share. She knows that the return on the Utility has a standard deviation of 40 per cent and the return on the Commodity has a standard deviation of 30 per cent. However, she does not know the exact covariance in the returns of the two shares. Jackie would like to plot the variance of the portfolio for each of three cases -covariance of 0.12, 0, a in order to understand how the variance of such a portfolio would react. Do the calculation for each of the extreme cases (0.12 and -0.12), assuming an equal proportion of each sharfe in Jackie's portfolio. 1 2 12 Part 1, 012 0.12: (0.5)"(p.4)2 + (0.512 (0.3)2 + 2(0.5)(0.5) (0.12) = 0.1225 Part 2, 0.0: (0.5) (0.4) (05) (0.3)+2(0.5)(0.5)(0.0) 0.0625 Part 3, 12--0.12: (0.5)2 ( .4)? + 0.6)2 (0.3)2 + 2(0.5)(0.5)(-0.12) = O.0025 5