Answer:
2 chaperones
Step-by-step explanation:
We will use the math operation division to find the answer. Division takes a total and divides it into equal amounts. We have a total of 72 students and need equal amounts in to each of the 9 groups.
72/9=8 students per group
Since each 4 students need a chaperone, then each group of 8 students needs 2 chaperones. 8/4=2.