If the price of a haircut is $10, the number of haircuts provided is 100. If the price rises to $15 per haircut, barbers will work much longer hours,...

If the price of a haircut is $10, the number of haircuts provided is 100. If the price rises to $15 per haircut, barbers will work much longer hours, and the supply of haircuts will increase to 300. The price elasticity of supply for haircuts between $10 and $15 using the mid-point method is