![](https://i.imgur.com/J4HWend.jpg)
Re: [中學] 排組
![](https://i.imgur.com/J4HWend.jpg)
求這兩題詳解 謝謝
(1) C(5,2)*C(8,2) = 10 * 28 = 280
(2) 4 * 7 + 3 * 6 + 2 * 5 + 1 * 4
= 28 + 18 + 10 + 4
= 60
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