Ok, so first of all there are 11 players to start off with. So, the first time the coach selects a player, there is a 5/11 chance, that there will be a girl picked. After this, the number on the bottom goes down to 10. Assuming there was a girl picked, the top number is now a 4, because there is now one less girl to be chosen. So now, you multiply the first number by the second number. This is because the first condition has to happen for the second condition to occur. I hope that explains everything.
