
To determine the probability of selecting a card with a number less than 9 from the given deck, follow these steps:
Thus, the probability of selecting a card with a number less than 9 is 0.8 (to one decimal place).
| $X_i$ | 5 | 6 | 8 | 10 |
| $F_i$ | 8 | 10 | 10 | 12 |
| X | 0 | 1 | 2 | 3 | 4 | 5 |
| P(X) | 0 | K | 2K | 3K | 4K | 5K |