基礎ECON-ELAS-018
A student reports PED as −1.5 and concludes demand is inelastic. The conclusion is:
A. Right, because any negative number is inelastic.
B. Right, because elastic demand must be positive.
C. Wrong, because a negative PED means supply, not demand.
D. Wrong. Elasticity is judged by the absolute value, and 1.5 is elastic.✓ 答案
解說
The law of demand makes PED negative. Classification uses |PED|. |−1.5| = 1.5 > 1, so demand is elastic. The sign records direction, not the elastic/inelastic label.