How to find out peoples birthdays by how many letters in their name?

Question: How to find out peoples birthdays by how many letters in their name!?

This guy came to our class and asked these questions to certain students

- Whats your name!?
- How many letters are in your full name!?
Then he did some math or some thing and told them their birthdays so i want to know how did he do it!!?Www@QuestionHome@Com

Best Answer - Chosen by Asker:

It is an impossibility!. Consider, there are currently almost 7 BILLION people alive on earth!. There are, however, 365!.25 days in the year!. That means, on average, there are 19,164,955!.51 persons who have a birthday each and every day!.
I would imagine that of that 19 millions persons, some have short names, some have long names, just as you see in the population at large!.
In other words, it is mathematically infeasible!Www@QuestionHome@Com

It was a trick!. You can't do it!. You can't pull coins out of people's ears, either, although you can make it LOOK like that is what you are doing!. He knew their birthdays beforehand, somehow!.Www@QuestionHome@Com