The most common question I get from people back home is: What's China like? My website: http://www.owendennis.com China blog: http://www.owendennis.com/blo...
Assuming you can run 2 miles now at a nice easy pace (conversational), within 20 weeks you should be able to train up to being able to finish marathon distance at that nice easy pace (between 10 and 12 minute miles) or approximately 4 to 5 hours.
For most runners however the average time for completing a marathon is 4 hours 30 minutes for men and 5 hours 10 minutes for women. The majority of recreational runners have other reasons for entering a marathon such as to achieve a lifetime goal or to raise money for a worthy cause.