Question

A chain letter is sent to five people on the first week of the year. Each of these five people then sends a copy of the letter to five more people during the second week of the year. Assuming that everyone who receives a letter participates, explain how you know with certainty that someone will receive a second copy of the letter later in the year.

Answer 1

ok, well, the number of people who get the letter is modeled by 5^(n), where n is the week of the year, does that make sense?

Answer 2

Hmmm, yes that makes sense.

Answer 3

So is that the reason we KNOW with certainty that someone will receive a second copy of the letter later in the year?

Answer 4

well, if you keep going with that thread, there are 52 weeks in the year, so by the end of the year 5^52 letters will have been sent out. this is on the oder of 10^36. there are only about 7billion people on the planet, so a lot more letters have been sent than there are people on the earth. therefore, some of those letters (actually, MOST of those letters) have been repeats

Answer 5

got it?

Answer 6

Oh o.k, thanks!

Answer 7

anytime