If the price of printers goes down, what happens in the market for ink cartridges: Demand increases.. Generally speaking, the lower the price, the greater the quantity demand: True. For the law of demand, as price rises, what happens to quantity demanded: it goes down. For the law of supply, as price rises, what happens to quantity supplied: it goes up. What are Substitute Goods: Items that may replace each other when used or consumed.. New robot technology increases productivity of car producers. What happens to market for cars: Supply shifts right. Price of cars increase. What happens to market for cars: No change in supply. Cost of steel increases. What happens to market for cars: Supply shifts left. The diagram represents a: increase in demand. Thousands of people leave a small town due to a factory closing down. Sales at the local grocery store become slow. What causes this change: Change in the number of buyers. Which of the following is likely to increase the demand for peanut butter: News that insects have destroyed much of the peanut crop and that there will be less peanut butter on the shelves in three months.. What does the red solid line on the graph show: Surplus