Sylvia has a two assets in her portfolio, asset a and asset b. asset a has a standard deviation of 40% and asset b has a standard deviation of 20%. 50% of her portfolio is invested in asset a and 50%

Sylvia has a two assets in her portfolio, asset a and asset

b. asset a has a standard deviation of 40% and asset b has a standard deviation of 20%. 50% of her portfolio is invested in asset a and 50% is invested in asset

b. the correlation for the asset a and asset b is .90. what is the standard deviation of her portfolio?