The average time is around 50 mins depending on how skilled you are. If you set yourself at a good steady pace and are at a moderate fitness level you should be able to run 10k in an hour or less.
The average finish time to finish a 10k road race in about 60 minutes.
No matter what your ability is, you should not feel that you need to be able to run at a certain speed to do 10k road race. Organizers consciously keep in mind that there are runners of varying ability and most organizers cater for all types.