²ⁿP₃ = 100 × ⁿP₂
2n!/(2n - 3)! = 100 × n!/(n - 2)!
2n(2n - 1)(2n - 2)(2n - 3)!//(2n - 3)! = 100 × n(n - 1)(n - 2)!/(n - 2)!
2n(2n - 1)(2n - 2) = 100 × n(n - 1)
2× 2n(2n - 1)(n - 1) = 100 × n(n - 1)
2n - 1 = 25
2n = 26
n = 13