1. **State the problem:** We are given a set of ordered pairs representing the number of tickets (input) and the total cost (output). We need to determine if the cost is a function of the number of tickets. 2. **Recall the definition of a function:** A relation is a function if every input (number of tickets) corresponds to exactly one output (total cost). 3. **Examine the ordered pairs:** The pairs are (1, 8.50), (3, 25.50), (5, 42.50), (6, 51), (7, 59.50). 4. **Check for repeated inputs:** Each input value (1, 3, 5, 6, 7) appears only once. 5. **Conclusion:** Since each input has exactly one output, the relation is a function. **Final answer:** Yes, the cost is a function of the number of tickets because each number of tickets corresponds to exactly one total cost.