To find the rate at which lemons are used in cups of lemonade per lemon, you can divide the total number of cups of lemonade by the number of lemons used.
Given:
- 3 lemons make 18 cups of lemonade.
To calculate the rate:
\[ \text{Rate (cups per lemon)} = \frac{\text{Total cups of lemonade}}{\text{Number of lemons}} = \frac{18 \text{ cups}}{3 \text{ lemons}} = 6 \text{ cups per lemon} \]
So, lemons are being used at a rate of 6 cups of lemonade per lemon.