Answer:
12.53%
Explanation:
Since there are only two assets in the portfolio, its standard deviation can be determined using the two-asset portfolio standard deviation provided below;
σP = (wA2 * σA2 + wB2 * σB2 + 2 * wA * wB * σA * σB * ρAB)^(1/2)
wA=proportion of the portfolio invested in X=60%
σA=standard deviation of return on X= 10%
wB=proportion of the portfolio invested in Y=40%
σB=standard deviation of return on Y =21%
ρAB= correlation between X and Y=.5
σP=(60%^2*10%^2+40%^2*21%^2+2*60%*40%*10%*21%*.5)^(1/2)
σP=12.53%