What is the price elasticity of demand compares the percent change in quantity demanded relative to the percent change in price - this is done by taking the change in quantity demanded by the change in price.
Example: Price Elasticity of Demand = Percent Change in Quantity Demanded
What determines it? Percent Change in Price
What is elastic and inelastic demand? Inelastic demand for a good is inelastic when the quantity demanded is unresponsive to a change in price.
Elastic demand for a good is elastic when the quantity demanded is highly responsive to change in price.