有3户人家共订了10份日报,每户人家至少2份,最多4份。问:一共有多少种不同的订法?()
2023-06-09
A. 6
B. 12
C. 18
D. 21
参考答案:A
B. 12
C. 18
D. 21
参考答案:A
首先保证每家至少2份,则分出去6份,剩余4份分3家,每家分到的为0---2份。所以4份可以分为:1 1 2或者 2 2 0
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