To determine the market quantity demanded at a price of $15 using Figure 4-2, you would typically look at the individual demand curves for the two consumers in the market at that price and sum their quantities demanded.
Without being able to see the actual figure and its demand curves, I can only guide you on the process:
- Locate the price of $15 on the vertical (price) axis of the graph.
- Find the quantity demanded by Consumer 1 at that price from their demand curve.
- Do the same for Consumer 2.
- Add the quantities demanded by both consumers together to find the total market quantity demanded at that price.
If you have the quantities from the graph for both consumers at $15, you can sum them to arrive at your answer.
If you can provide the quantities for the consumers at that price, I can help you sum them up to find the correct answer! Otherwise, you should refer back to the figure to find the individual quantities and complete the calculation.