打完所有对局这就简单了（因为不考虑甲胜两局就不打的情况）C（3,2）=3,所以胜两局的概率为3*0.6*0.6*0.4=0.432,还有胜3次0.6*0.6*0.6=0.216,共为0.648.
而打五局有胜3局的C(5,3)=10 10*0.6*0.6*0.6*0.4*0.4=0.3456,胜4局C（5,4）=5,5*0.6*0.6*0.6*0.6*0.4=0.2592,胜5局0.6*0.6*0.6*0.6*0.6=0.07776 所以共为0.68256.（事实上凭经验甲胜的概率大肯定多打几局要稳妥些）