2 Pnk for n = 100, k = 5: 100 * 99 * 98 * 97 * 96 = nine billion thirty four million five hundred and two thousand four hundred possibilities. If I can crank out one try per second and never sleep, I should be able to get through them all in only 286.482 years. Of course, on average I’d hit the correct combination halfway through, so that’s a mere 143.241 years. Totally doable!
