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if 5(p r)=6(p (r-1)) find r....

if `5_(p_ r)=6_(p_ (r-1))` find r.

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`5_(p_ r)=6_(p_ (r-1))`
`(5!​)/( (5−r)!)=(6!​)/({6−(r−1)}!)`
` (5!)/((5−r)!)​=(6×5!​)/((7−r)!)`
` 1/((5−r)!)​=6/((7−r)(6−r)(5−r)!)`
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