You are planning to make investment into three stocks, stock A, stock B and stock C. If the following information is given for them (KA: Rate of return of stock A):

Variance(KA)=360

Variance(KB)=286

Variance(KC)=120

Covariance(KA, KB)= - 98

Covariance (KA, Kc)=260

Covariance (KC, KB)= - 118

If you form a portfolio investing 30% of your savings into stock A (WA=30%), 35% of your savings into stock B (WB=35%) and 35% of your savings into stock C (WC=35%), what will be the standard deviation of rate of return of your portfolio?