1. **State the problem:** We have 1000 tickets sold in a raffle, and one winning ticket is picked at random. Jack has one ticket. We want to find the probability that Jack's ticket is the winning ticket. 2. **Formula for probability:** The probability of an event happening is given by: $$\text{Probability} = \frac{\text{Number of favorable outcomes}}{\text{Total number of possible outcomes}}$$ 3. **Apply the formula:** - Number of favorable outcomes = 1 (Jack's ticket) - Total number of possible outcomes = 1000 (total tickets) So, $$\text{Probability} = \frac{1}{1000}$$ 4. **Interpretation:** This means Jack has a 1 in 1000 chance of winning the raffle. **Final answer:** $$\boxed{\frac{1}{1000}}$$