You ve paid 120 for membership to a racquetball club Court time is 5 per hour Let x the number of hours you play Part a Write an equation that represents the total cost C Part b Write an equation that represents the average cost A per hour Part c Use the graph of the model shown below to estimate the number of hours you must play before the average cost per hour drops to 10 per hour 220 18 16 14 12 10 8 6 4 2 10 20 8 0 70 80 90 100