Answer:
This is the table that the question is referring to:
Price QJ QS
5 4 2
10 3 1
15 2 0
20 1 0
Total market demand is the sum of the individual market demands. In this market, it is the sum of the market demand of Jake and Sue.
Market demand at the price of $5 is 7 pizzas.
Market demand at the price of $10 is 4 pizzas.
Market demand at the price of $15 is 2 pizzas.
Market demand at the price of $20 is 1 pizza.