Plz give me the solution ????

Plz give me the solution ???? rrec nswer If "P = 110 then the value of r is: (b) 10 (d) none of these

^{11} P_{r} = 110 \Rightarrow \frac{11!}{(11 - r)!} = 110 \Rightarrow \frac{11 \times 10 \times 9!}{(11 - r)!} = 110 \Rightarrow (11 - r)! = 9! \Rightarrow 11 - r = 9 \Rightarrow r = 11 - 9 \Rightarrow r = 2