Answer:
There will be 4 students in each group and there will be 9 groups.
Explanation:
There are 16 sixth graders and 20 seventh graders in the robotics club.
As we have to find the number of students that will be in each group if each group has the greatest possible numbers of club members, so we will find the HCF or highest common factor of 16 and 20.
16 = 2 x 2 x 2 x 2
20 = 2 x 2 x 5
HCF = 2 x 2 = 4
So, 16 sixth graders will be divided in
groups
20 seventh graders will be in
groups
total groups =

Hence, total there will be 9 groups with 4 students in each group.