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

來源: 於 2010-06-18 20:10:28 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：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.