She sends the list to Barry, Bert, Bob, and Benny. If everyone participates during the second cycle, a name is added to each of the 5 lists and 5 copies are made of each list bringing our total participants to 6 and our total lists to 25. Barry sends copies to Carl and Casper plus 3 other people. Bert sends copies to Carol and Clay plus 3 other people. If everyone participates during the third cycle, a name is added to each of the 25 lists and 5 copies are made of each list bringing our total participants to 31 and our total lists to 125.
Lets look at the problem a little differently.
The answer is, when your name gets into the top 5 slots. Abigail, Bert, Barry, etc all started out with their name in the first 5 slots. At tier 6 we have a dilemma. The following chart shows how many people have sent money to the top 5 names on the list if all the copies that are sent out are successful in bringing in 5 new participants each time. This is because every single person who ever received a list up to now has had her name in position number 1.