1. The problem asks: Which equation can you use to find $c$, the cost of each teacup? 2. We are given four equations: - $4c - 18 = 42$ - $18c + 4 = 42$ - $4c + 18 = 42$ - $18c - 4 = 42$ 3. To find the cost $c$, we need an equation that correctly models the situation. Since the question does not specify the context, we look for an equation that can be solved for $c$ easily and makes sense. 4. Let's check each equation for solvability: - For $4c - 18 = 42$: Add 18 to both sides: $4c = 42 + 18 = 60$ Divide both sides by 4: $c = \frac{60}{4} = 15$ - For $18c + 4 = 42$: Subtract 4 from both sides: $18c = 42 - 4 = 38$ Divide both sides by 18: $c = \frac{38}{18} \approx 2.11$ - For $4c + 18 = 42$: Subtract 18 from both sides: $4c = 42 - 18 = 24$ Divide both sides by 4: $c = \frac{24}{4} = 6$ - For $18c - 4 = 42$: Add 4 to both sides: $18c = 42 + 4 = 46$ Divide both sides by 18: $c = \frac{46}{18} \approx 2.56$ 5. Without additional context, all equations can be solved for $c$, but the problem likely expects the equation that correctly models the cost. 6. Since the question is "Which equation can you use to find $c$?" and all are solvable, the best choice is the first equation $4c - 18 = 42$ because it leads to a clean integer solution $c=15$. Final answer: The equation $4c - 18 = 42$ can be used to find $c$, and the cost of each teacup is $15$.