Answer:
2 groups of 30
Step-by-step explanation:
If you add together the two classes, you get 60 students. because you want to find the largest possible equal groups, with no students left over, you can divide all the students (60) by two, and you get 30 students in two groups.
for the columns where is less than or equal zero, use the first line of the function to calculate the value of f(x)

for every x greater than zero, use the second line to determine the value

hope this helps and gives some insight what to do.
if there are open questions left, feel free to ask them in the comments
have a beautiful day
-Alex
X> or equal - 10
d is the solution