n(n−1)Pr−1=?n(n-1)P_{r-1}=?n(n−1)Pr−1=? An−1Pr^{n-1}P_rn−1PrBnPr−1^nP_{r-1}nPr−1CnPr^nP_rnPrDn(n+1)Prn(n+1)P_rn(n+1)PrAnswer: nPr^nP_rnPr Read Explanation: n(n−1)Pr−1n(n-1)P_{r-1}n(n−1)Pr−1=n×(n−1)!(n−1)−(r−1)=n\times\frac{(n-1)!}{(n-1)-(r-1)}=n×(n−1)−(r−1)(n−1)!=n!(n−r)!=\frac{n!}{(n-r)!}=(n−r)!n!=nPr=^nP_r=nPr Read more in App
