You play a coin flipping game with 5 coins. On round 1 you flip all of them. On round 2, you pick up all the ones that came up tails (leaving all the heads alone) and flip them again. You continue to do this until all the coins are heads. For example:

Round 1:  H T T H T
Round 2:  - H T - H
Round 3:  - - T - -
Round 4:  - - T - -
Round 5:  - - H - -

Done in 5 Rounds.

What is the expected number of rounds you'll need to finish the game?
What is the probability you will finish the game in 3 rounds or less?

(In reply to To Nikki by bernie)

Ahhh, yes. I only said the probability of 3 rounds, not 3 rounds or less. The actual chance of winning in 3 rounds OR LESS is 51.29%

I couldn’t tell if you were disagreeing or not, but I still think the way I found the expected number of rounds to win the game is correct.

I’m still curious what this 3.79… number everyone is talking about is.

Posted by nikki on 2004-10-14 20:46:18