So blue is a recessive trait so it would be bb and brown eyes are dominant so it could be Bb or BB. So when you cross them (BB and bb) you get 100% Bb which is brown eyes. If you cross Bb and bb you get a 50 50% chance of having 2 with blue eyes and two with brown eyes. It would be 2bb and 2Bb. And the other will be 4Bb. Hope this helps!
