Question

Laura and her two friends share a gym plan. The gym charges a flat rate of $60 per month, which the 3 friends share equally. In addition, the gym charges 5 dollars per class taken. Each friend pays for his own class taken. Laura's share of the current gym bill is $105. Which equation determines how many classes Laura took? A. 60x + 5 = 105 B. 90 + 5x = 105 C. 20 + 5x = 105 D. 20x + 5 = 105

Answer 1

The flat rate of the plan is $60, and this rate is divided by 3, so each friend will pay 60 / 3 = $20 of the flat rate.

Also, each class costs $5, so if the number of classes is x, the variable cost of the plan is 5x.

Therefore, if Laura took x classes and her share was $105, we have the following equation:

`\begin{gathered} \text{cost}=\text{fixed cost + variable cost} \\ \text{cost}=20+5x \\ \text{cost}=105\to20+5x=105 \end{gathered}`

This equation determines how many classes Laura took.

The option that corresponds to this equation is C.