Question:medium

If \({}^nC_r={}^{\,n}C_{r-1}\) and \({}^{\,n}P_{r-1}=9\,{}^{\,r}P_r\), then \((n,r)=\)

Show Hint

Identity: \[ \boxed{ {}^nC_r={}^nC_{r-1} \Longrightarrow 2r=n+1. } \]
Updated On: Jul 18, 2026
  • \((19,9)\)
  • \((19,10)\)
  • \((10,19)\)
  • \((9,19)\)
Show Solution

The Correct Option is B

Solution and Explanation

Was this answer helpful?
0

Top Questions on Combinatorics

Questions Asked in TS PGECET exam