A gym charges a one-time registration fee of $50 and a monthly membership fee of $35. If a member paid a total of $330, for how many months did they use the gym?

✓ Correct Answer: Option C

Let 'm' be the number of months. The total cost is represented by the equation $50 + $35m = $330. Subtracting $50 gives $35m = $280. Dividing by $35 yields m = 8.