Question

You have a 4-card deck containing a queen, a jack, a 10, and a 9. You draw a random card, then put it back and draw a second random card. Use a tree diagram to calculate the probability that you draw exactly 1 "face" card (a queen or a jack). What's the fraction?

Answer 1

|
+---10
| +---10
| +---9
| +---J
| \---Q
+---9
| +---10
| +---9
| +---J
| \---Q
+---J
| +---10
| +---9
| +---J
| \---Q
\---Q
+---10
+---9
+---J
\---Q

So, in the top half we have a face card listed 2 times and another 2 times out of 8 pairings.
In the bottom half it is flipped around, but the probability.
8 times out of 16 one face card.

Answer 2

Thank you, you were right. It was 1/2.