If ${ }^n P_4=1680$, then $n=$

Question

Aicharya · Accepted Answer

$\begin{aligned} & \text {Since, }{ }^n P_4=1680 \ & \Rightarrow \quad n(n-1)(n-2)(n-3)=1680 \ & \Rightarrow \quad n(n-1)(n-2)(n-3)=8 \times 7 \times 6 \times 5 \Rightarrow n=8 \end{aligned}$ Hence, option (d) is correct.

If \({ }^n P_4=1680\), then \(n=\)

Solution