<span>Each team in the softball league plays each of the other teams exactly once. For every game, there is 2 team playing. The order is not important because A vs B is same as B vs A So you just need to makes a combination of 2 that have a result of 21. If there is t number of teams, the number of matches would be: tC2 = t!/2!(t-2)! = 21 </span>t! / (t-2)! = 21 *2 (t)(t-1)= 42 t^2 -t -42=0 (t-7)(t+6) t=7 ; t=-6
