In this experiment, we have a selection of cards numbered 5, 10, and 15. The probability model for this experiment can be expressed as follows:
Let \( X \) be the random variable representing the numbers on the cards. The possible values of \( X \) are the numbers on the cards.
The possible values of \( X \) in ascending order are:
- \( 5 \)
- \( 10 \)
- \( 15 \)
Thus, the values of \( x \) are: \[ x = { 5, 10, 15 } \]