<P> PED is a measure of the sensitivity of the quantity variable , Q , to changes in the price variable , P. Elasticity answers the question of the percent by which the quantity demanded will change relative to ( divided by ) a given percentage change in the price . For infinitesimal changes the formula for calculating PED is the absolute value of ( ∂ Q / ∂ P ) × ( P / Q ) . </P>
the elasticity of demand for an item is determined in part by the question
the percent by which the quantity demanded will change relative to ( divided by ) a given percentage change in the price