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n \text { if } ^ { 2 n } C _ { 3 } : ^ { n } C _ { 3 } = 11 : 1 |
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Answer» 2nC3 : nC3 = 11:1 (2n)(2n-1)(2n-2)/(3×2×1) : (n)(n-1)(n-2)/(3×2×1) = 11 : 1 (2n-1)2(n-1):(n-1)(n-2) = 11:1 4n-2 = 11n-22 22-2 = 7n so n = 20/7 |
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