[中學] 重複組合

[yuchiao0921 (挑戰在我就在)]

X1+X2+X3+X4+X5=21

X1~X5都是非負整數解

請問滿足下列條件有幾組解

0<=X1<=3,1<=X2<4,X3>=15

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推 KitWoolsey  :把X2跟X3的1跟15先扣掉 變成總合=5
→ KitWoolsey  :0<=X1<=3,0<=X2<=2 救好解了吧
→ yuchiao0921 :謝謝