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Here's what i tried to do:

$$^{2n}C_3:^nC_3 = 12 : 1$$ $$\frac{^{2n}C_3}{^nC_3} = \frac{12}1$$ $$\frac{\frac{(2n)!}{(2n-3)!}}{\frac{n!}{(n-3)!}} = 12$$

However i don't know what to do after this step.

Note: There are two extremely similar questions next to each other, i.e $^{2n}C_3:^nC_3 = 12 : 1$ and $^{2n}C_3:^nC_3 = 11 : 1$ so i think one of them might be a misprint. But then i'd need a hint for the other.

Aayush Agrawal
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1 Answers1

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Hint: $(2n)! = 2n(2n-1)(2n-2)(2n-3)!, n!= n(n-1)(n-2)(n-3)!$

DeepSea
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