The current price in the agricultural lettuce market is set by the government, and is such that the price of lettuce is 25% higher than equilibrium price and 100 heads of lettuce are demanded.
Suppose that the elasticity of demand for lettuce is -0.50. What would be the equilibrium quantity of lettuce if the government removed its restriction on the price of lettuce?
(You can assume that the elasticity of demand is constant along the demand curve)
The answer is 112.5, but how is that answer found?