If Dilly brings two green gloves then they will not necessarily be
a matching pair (since they could both be left-hand gloves or both
be right-hand gloves). Similarly, two blue gloves could
both be right-hand gloves. In the same way, three blue
(or green) gloves could all be right-handed. However,
if Dilly brings all four blue gloves then these will include a
This problem is taken from the UKMT Mathematical Challenges.