1. **State the problem:** Jace bought 7 fish sticks for 17.50. We want to find the cost for 6 fish sticks. 2. **Formula used:** Since the cost is proportional to the number of fish sticks, we use the ratio formula: $$\frac{\text{cost}_1}{\text{quantity}_1} = \frac{\text{cost}_2}{\text{quantity}_2}$$ 3. **Set up the proportion:** $$\frac{17.50}{7} = \frac{x}{6}$$ where $x$ is the cost for 6 fish sticks. 4. **Solve for $x$:** Multiply both sides by 6: $$x = 6 \times \frac{17.50}{7}$$ 5. **Simplify the fraction:** $$x = 6 \times \frac{\cancel{17.50}}{\cancel{7}}$$ Since 17.50 divided by 7 is 2.5: $$x = 6 \times 2.5$$ 6. **Calculate the final cost:** $$x = 15$$ **Answer:** The cost for 6 fish sticks is 15.