A. using the regular percentage change method, what is the price elasticity of supply starting at a price of $40 per umbrella and moving to a price of $60 per umbrella? 1000 b. using the regular percentage change method, when the price of umbrellas falls from $100 per umbrella to $80 per umbrella, the decrease in price is a -1.33 % decrease. the decrease in quantity supplied is a % decrease. therefore, the elasticity of supply is . c. if the elasticity of supply for umbrellas is 1.1, then an increase in the price of umbrellas of 20% will the quantity supplied by %.