There are 25 squares in the picture.If you put 5 coins in the square and three can be only one in each line and column,how many ways can you put the coins?
就是第2句不太明白
关键就是那个three
如果按题意做(three)就太简单了
也不符合平常做的常理
人气:266 ℃ 时间:2020-04-03 09:03:44
解答
图中有25个正方形.放5枚硬币在正方形里,其中只允许3枚在同一行或列,你有多少种排法?
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