I am needing help with this, can't figure out the correct method.

Suppose the U.S. Index has an expected return of 10% and a standard deviation of 15%. The Latin America Index has an expected return of 15% and a standard deviation of 30%. The two indices have a correlation coefficient of 0.30. Plug in these numbers into the worksheet 2 securities, 100 portfolios on my file PS7 student worksheets for parts b and c below.

a. Calculate (using formulas, not the Excel file) the expected return and standard deviation of a portfolio that is weighted 79% in the U.S. and 21% in Latin America.