P(X=0,Y=1)=0.2*0.5=0.1P(X=0,Y=2)=0.2*0.2=0.04P(X=0,Y=3)=0.2*0.3=0.06P(X=1,Y=1)=0.3*0.5=0.15P(X=1,Y=2)=0.3*0.2=0.06P(X=1,Y=3)=0.3*0.3=0.09P(X=2,Y=1)=0.4*0.5=0.2P(X=2,Y=2)=0.4*0.2=0.08P(X=2,Y=3)=0.4*0.3...高手！那第二问怎么做啊！P(Z=1)=P(X=0)*P(Y=1)=0.1
P(Z=2)=P(X=0)*P(Y=2)+P(X=1)*P(Y=1)=0.19
P(Z=3)=P(X=0)*P(Y=3)+P(X=1)*P(Y=2)+P(X=2)*P(Y=1)=0.32
P(Z=4)=P(X=1)*P(Y=3)+P(X=2)*P(Y=2)+P(X=3)*P(Y=1)=0.22
P(Z=5)=P(X=2)*P(Y=3)+P(X=3)*P(Y=2)=0.14
P(Z=6)=P(X=3)*P(Y=3)=0.03