A factory of 500 workers produces tennis balls and volleyballs. Each worker could produce either 20 tennis balls or 10 volleyballs per day.

1. Draw the PPF for this factory's production per day and label it PPF₁. In your graph, place the number tennis balls on the x-axis and the number of volleyballs on the y-axis. (Hint: It is a straight line.)
2. Find the equation of the PPF.
3. Find the opportunity cost of 1 volleyball.
4. Find the opportunity cost of 1tennis ball.
5. Is there a relationship between the opportunity cost and the slope of the PPF? If yes, what is the relationship?
6. Describe the differences between a linear PPF and a PPF that is bowed-outwards from the origin using the concept of opportunity cost.
7. Suppose the workers invent a new method to produce tennis balls. With the implementation of the new method, each worker can produce 30 tennis balls per day instead of 20. Draw the PPF and label it PPF₂. Find its equation. What does this example suggest about the relationship between the PPF and technological improvements?