A restaurant at a popular Colorado casino provides priority service to player's card holders. The restaurant has 10 tables or booths where customers may be seated. The service time (time a booth or table is occupied) averages 42 minutes once a party is seated. The customer arrival rate is 8 parties per hour, with the parties being equally divided between card holders and people without player's cards. 

What is the average time that parties without player's cards wait to be seated?