These two events both have probability of 0.25 (or 9 possible cases out of
the 36 equally likely outcomes)
There are 6 outcomes with a blue 3, but we will have counted 3 of them
allready with the 9 cases with two odd.
So we have n=9+9+6-3=21 favourable outcomes out of a total of 36, so
the probability is 21/36=7/12.