Answer:
it would decrease by 10%
Step-by-step explanation:
Price elasticity of demand measures the responsiveness of quantity demanded to changes in price of the good.
Price elasticity of demand = percentage change in quantity demanded / percentage change in price
percentage change in price = ($10 - $8) / $8 = 0.25 x 100 = 25%
0.4 = percentage change in quantity demanded / 25%
percentage change in quantity demanded = 25% x 0.4 = 10%