Độ co giãn của cầu theo giá =-3 có nghĩa là gì

Step-by-step explanation:

What does price elasticity of demand = -3 mean ?

Price elasticity of demand = change in % of demand / change in % of price

So

change in % of demand / change in % of price = -3

or

change in % of demand = -3 * change in % of price

means that

when price is increased by 10 percent, the demand is decreased by 30 percent.

This happens when there is a possibility of substitution, such as coffee and tea.  When coffee prices are increased by 10%, the demand of coffee is decreased by 30%.