基礎ECON-ELAS-002
If the price elasticity of demand for a good is 0.5, a 10% increase in price will cause the quantity demanded to:
A. Decrease by 5%✓ 答案
B. Decrease by 20%
C. Increase by 5%
D. Decrease by 10%
解說
PED = %ΔQd / %ΔP. Given PED = 0.5, a 10% price increase leads to %ΔQd = 0.5 × 10% = 5%. Since price and quantity move inversely, quantity decreases by 5%. B would be PED=2, C has wrong sign, D implies unit elasticity.