I got a little bit of progress, maybe it will help...
P(A pair of 2 black boxes)=((3C0)*(7C2))/(10C2)=0.46666 Where C is the binomial coefficient, in the same way:
P(A pair of 2 white boxes)=0.0666
P(1 black and 1 white)=0.46666
What do I do from here ?