LESSON 21 SESSION 3 Apply It Use what you learned to solve these problems. Four friends go on a camping trip. They decide to share the cost equally. They spend $27.68 on food and $42 to reserve the campsite. You can use the equation 4c = 42 + 27.68 to find each person's share of the cost. a. What does the variable c represent? Explain how the equation 4c = 42 + 27.68 represents the situation.