Will, Jill, and Phil are all wheat farmers. The wheat industry is perfectly (purely) competitive. The first chart shows how much each farmer produces at different price levels. The second chart shows each farmer’s minimum average total cost (ATC), average variable cost (AVC), and marginal cost (MC).
Based on this data (assuming these three are the only producers), plot the industry supply curves: one for the short run and one for the long run
The Correct Answer and Explanation is :
To create the industry supply curves, we need to analyze the data from both charts. The steps are as follows:
Step 1: Understanding the Individual Supply Curves
In a perfectly competitive market, each farmer’s supply curve is determined by their marginal cost (MC) curve above the average variable cost (AVC). This is because a firm will supply output as long as the price covers at least the AVC in the short run. In the long run, firms will only stay in business if the price is equal to or greater than their minimum average total cost (ATC).
Step 2: Constructing the Short-Run Industry Supply Curve
- The short-run supply curve for each farmer corresponds to the MC curve above the AVC.
- The industry supply curve is found by summing up the individual supply curves of Will, Jill, and Phil at each price level.
- As long as the price covers AVC for each farmer, they will produce wheat. If the price drops below AVC, they will shut down in the short run.
Step 3: Constructing the Long-Run Industry Supply Curve
- In the long run, only firms that can cover their minimum ATC will stay in the market.
- If the price is below minimum ATC, firms exit, reducing supply.
- The long-run supply curve is more elastic because firms can enter or exit the market.
Now, I will generate the industry supply curves for both the short run and long run.
Explanation of the Industry Supply Curves
In a perfectly competitive wheat market, the industry’s supply curve is derived from individual farmers’ marginal cost (MC) curves above their average variable cost (AVC). Here’s how the short-run and long-run supply curves differ:
Short-Run Industry Supply Curve
- Summing Individual Supply: The short-run industry supply curve is obtained by summing up the quantity supplied by Will, Jill, and Phil at each price level.
- Shutdown Condition: Each farmer only produces if the price is at or above their AVC. If the price drops below AVC, they stop producing in the short run.
- Steeper Shape: Since firms are constrained by existing capacity, the short-run supply curve is relatively steeper.
Long-Run Industry Supply Curve
- Firm Entry and Exit: In the long run, firms will only remain in the market if the price covers their minimum ATC. If the price falls below a farmer’s ATC, they exit.
- Flatter Curve: The long-run supply curve is typically flatter because firms can freely enter or exit the market. This means that over time, the industry adjusts to ensure firms are only producing if they can cover all costs, including fixed costs.
- Lower Supply at Low Prices: If the market price falls below the lowest ATC (here, $12), some farmers exit, reducing total industry supply.
Key Takeaways
- In the short run, all three farmers produce as long as price covers AVC.
- In the long run, only farmers whose ATC is covered remain in business.
- The long-run curve is more elastic because firms adjust production by entering or exiting the market.
This explains why the short-run and long-run supply curves differ in shape and behavior.
