Bob is a retired teacher who lives in Philadelphia and provides math tutoring for extra cash. At a wage of $50 per hour, he is willing to tutor 7 hours per week. At $65 per hour, he is willing to tutor 10 hours per week.Using the midpoint method, the elasticity of Bob’s labor supply between the wages of $50 and $65 per hour is approximately ___ , which means that Bob’s supply of labor over this wage range is ___ .