11 p r = 12 p r-1Find rPermutation

1.	11 p r = 12 p r-1Find rPermutation
Answer» Sorry , last one was wrong , $$r=9 & 16$$ by solving eq. $$ r^2 -25r+144=0$$<br>$$\\frac{11!}{r(r-1)!}= \\frac{12×11!}{(r-1)!} =$$ $$\\frac{1}{r} =12$$ $$r=\\frac{1}{12}$$<br>r=9<br>r = 1/12

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