回複：南斯拉夫奧賽題：兩位數（2星）

來源: 於 2009-07-06 12:07:32 [舊帖] [給我悄悄話] 本文已被閱讀：次

There are two solutions:
15 and 45. 15*7=105, 45*9=405. That's all.