What Is the Probability of Drawing a 2, 3, or 4 as the 13th Card?

[jackbauer]

Hi ppl, was hoping someone could point me in the right direction with this problem. 12 cards are dealt from a standard 52 pack of playing cards, 6 are kept face down, the others are 2 kings, two 3s, a 7 and a jack. Calculate the probability the 13th card drawn is a 2,3 or a 4.
Could someone please give me some help on how to proceed, thx
Jack

 

[mathman]

You have 6 known cards including 2 3's. There are 46 unknown cards including 4 2's 2 3's and 4 4's, a total of 10 desired cards. Therefore the probability that the next card chosen is one of these is 10/46. The 6 previously chosen, but unknown, cards are irrelevant.