Test students' ability to calculate and interpret price elasticity of demand from numerical and graphical data; classify demand as elastic, inelastic, or unitary; explain key determinants (substitutes, necessity vs luxury, income share, time horizon); and apply elasticity to firm pricing decisions including revenue effects of price changes, optimal markup strategies (elasticity–marginal revenue link), and tax or promotion responses. Include short calculations, brief graph interpretations, and a scenario requiring a justified pricing recommendation.