I help with this question but can you please provide a detailed explanation as well as any formulas needed

1.) Mary Guilott has collected the following information about stock of Firm A and Firm B. Expected Return 15% Firm A Firm B Standard Deviation 20% 24% 18% Correlation coefficient: 0.60 If Mary invests 10% of her money in stock A and 90% in Stock B, what is the portfolio's expected rate of return and standard deviation? (5 points)