+130516 (n+3)(n+2)! / (n+1)! = 30 .... note... (n+2)! / (n + 1)! = (n + 2) ......so we have
(n+ 3) (n + 2) = 30
n^2 +5n + 6 = 30
n^2 + 5n - 24 = 0 factor
(n + 8) (n - 3) = 0 so...n = -8 or n = 3 reject -8, since this would produce a negative factorial and factorials only apply to non-negative integers [ and, in advanced math courses, positive fractions, as well ]
So....n = 3
