please explain how to calculate weights

(13-3) You want to assess the expected return and risk of your portfolio, which contains three stocks You are basing your assessment on a simple forward-looking model based on three states of the world The weights in your portfolio are 25% in Stock A, 45% in Stock Band 30% in Stock C. Your assessment of the probable returns of these three stocks in the states of the world are given in the table below. Prob Stock A Stock B Stock C Boom 0.20 0.12 0.18 0.03 Normal 0.60 0.05 0.06 0.07 Bust 0.20 -0.06 0.11 0.02 Calculate the expected return and standard deviation of your portfolio based on these assumptions