Final answer:
If there are only 20 students in attendance, 5 pizzas would be required.
Step-by-step explanation:
In order to determine how many pizzas would be required if there are only 20 students in attendance, we can set up a proportion using the information given:
8 medium pizzas / 32 students = x pizzas / 20 students
To solve for x, we can cross-multiply:
8 * 20 = 32 * x
160 = 32 * x
Dividing both sides by 32, we get:
x = 160 / 32 = 5
Therefore, 5 pizzas would be required if there are only 20 students in attendance.