Question

You have a three-card deck containing a king, a queen, and a jack. You draw a random card, then without putting it back you draw a random second card from the ones that are left. Use a tree diagram to calculate the probability that you draw exactly one jack.

Answer 1

After you have drawn two cards, there will be one left. If that card is a Jack, you have a failure. Two times out of three, you succeed in getting the Jack. In no case is it possible to get more than one; there is only one in the deck.