Consider the graph. Move point A to the correct position on the demand curve when price is $40. Next, move point B to the correct position on the demand curve when price is $10. Now, consider a movement along this demand curve from A toB.

100 90 A B 80 70 60 Price ($) 50 40 30 20 10 0 100 200 300 400 500 600 700 800 900 1,000 Quantity (thousands)