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Question Number 193864 by pascal889 last updated on 21/Jun/23
Answered by MM42 last updated on 21/Jun/23
$$\frac{\frac{{n}!}{\left({n}−\mathrm{5}\right)!}}{\frac{{n}!}{\mathrm{4}!\left({n}−\mathrm{4}\right)!}}=\mathrm{144}\Rightarrow{n}−\mathrm{4}=\mathrm{6}\Rightarrow{n}=\mathrm{10}\checkmark \\ $$