6 . Calculating the price elasticity of supply Charles is a stay-at-home parent who lives in New York City and teaches tennis lessons for extra cash. At a wage of $25 per hour, he is willing to teach 6 hours per week. At $35 per hour, he is willing to teach 16 hours per week. Using the midpoint method, the elasticity of Charles’s labor supply between the wages of $25 and $35 per hour is approximately , which means that Charles’s supply of labor over this wage range is .