[pococurante]

Villain's possible hands, + whether the 5 paired him:

234 - no
235 - yes
245 - yes
345 - yes

There's a 75% chance the 5 paired him.

(I don't know just what a bike card is, but since you said there are 12 left after 4 were dealt, I assume it means 2, 3, 4, 5)