Consider the following table showing quantity demanded for a commodity at different prices

Answer The correct answer is (d.) the arrow representing the price effect points down and the arrow representing the quantity effect points up. From the information provided in the table, the price drops from $400 to $350 (i.e., the price arrow points down) and the quantity demanded goes up from 600 to 1,200 (i.e., the quantity arrow points up). Answer (a.) is incorrect because it postulates that both changes are in the same direction, specifically, up. Answer (b.) is incorrect because, while correctly postulating a smaller price effect than quantity effect, it again postulates incorrectly that quantity goes up. Answer (c.) is incorrect because it incorrectly postulates that total revenue and price move in the same direction when, in fact, price goes down and total revenue goes up.