Question

Two people are attempting to roll high numbers with there dice. Player 1 has a 20 sided dice. Player 2 has a 30 sided dice. Player 2 says that to be fair he will re-roll any roll that's higher than 20 until he gets a result of 20 or lower. Is this a fair contest or does player 2 have an advantage?

Answer 1

It is fair, as player 1 has 20 possible numbers. Player 2, although having a 30 sided dice is essentially ignoring 21-30, as if these numbers come up they simply re-roll the 30 sided dice. Therefore player 2 only can accept number 1-20, the same as what player 1 has.