I want to know the working out for this question and where the numbers coming from the last answer for this question was very confusing as i dont know where 2 and 0.5 came from.

thanks

What is the portfolio risk from this portfolio, as measured by standard deviation (to one decimal place)? Industrial Retail Allocation 29% 71% Return 9.4% 8.5% Risk 8.5% 5.5% (Std. Dev.) Correlation (p) between Industrial and Retail Sectors = 0.49 Covariance between Industrial and Retail Sectors = 0.00229 Answer = 5.5%