P{X=0}=C(15,2)/C(20,2)=15*14/(20*19)=21/38
P{X=1}=C(15,1)*C(5,1)/C(20,2)=15*5/[(20*19)/2]=75/190=15/38
P{X=2}=C(5,2)/C(20,2)=5*4/(20*19)=20/380=1/19
P{X=0}=C(15,2)/C(20,2)=15*14/(20*19)=21/38
P{X=1}=C(15,1)*C(5,1)/C(20,2)=15*5/[(20*19)/2]=75/190=15/38
P{X=2}=C(5,2)/C(20,2)=5*4/(20*19)=20/380=1/19