number of face cards in a deck of 52 cards = 12
total number of cards = 52
ways of choosing 'n' cards from 52 cards = ⁵²Cⁿ = 52!/(n!)(52-n)!
ways of choosing 'n' face cards = ¹²Cⁿ = 12!/(n!)(12-n)!
Probability = favorable outcomes/total outcomes
Probability of choosing n face cards = ¹²Cⁿ/⁵²Cⁿ
Probability of choosing n face cards = (12!/(n!)(12-n)!) / 52!/(n!)(52-n)!
= [ 12! * (52-n)! ]/[ (12-n)! * 52!)