There are 39 students in the bike club.
All but 8 of them participated in a race.
What is the total cost each student who entered the race paid $6?
O $148
O $162
O $186
O $234
If all but 8 students participated in the race, then 39 - 8 = <<39-8=31>>31 students entered the race.
The total cost each student paid is 31 * $6 = $<<31*6=186>>186.
The correct option is O $186. Answer: \boxed{O\ \$186}.