For those interested in the 21 game, if you go second, always end on a multiple of 4. No matter what the first person says, you can always end on a multiple of 4, and as 20 happens to be a multiple of 4, you win, as the first player must then say 21. In other words, she gave him the opportunity to win the first round, he failed miserably, and then she never let him win for the next two rounds.