Which formula represents price elasticity of demand?

• A. E_d = (% change in price) / (% change in Q_d)
• B. E_d = (% change in Q_d) / (% change in price)
• C. E_d = (% change in Q_d) / (% change in income)
• D. E_d = (% change in income) / (% change in price)

Answer: (B)