(19*0+12*1+1*2)/32=7/16, right?

来源: 于 2010-06-18 20:10:28 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

19 cases, no pumps need repairing;
12 cases, 1 pump needs repairing;
1 case (all pumps are out of order), 2 pumps need repairing.