Q8 of 195 Page 16

If (n + 1)! = 90 [(n – 1)!], find n.

Given: (n + 1)! = 90 [(n – 1)!]


To Find : n ?


⇒ (n + 1) × (n) × (n-1)! = 60 [(n – 1)!]


⇒ (n + 1) × (n) = 90


⇒ (n + 1) × (n) = 10 × 9


n = 9


Hence, n = 9


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