Answer:
The music director can form a total of 15 groups
6 Sixth grade students per group
5 Seventh grade students per group
Step-by-step explanation:
Sixth grade students = 90
Seventh grade students = 75
Find the highest common factor of 75 and 90
90 = 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90.
75 = 1, 3, 5, 15, 25, 75
The highest common factor of 75 and 90 is 15
Therefore, the music director can form a total of 15 groups
Sixth grade students per group = 90 / 15
= 6 Sixth grade students per group
Seventh grade students per group = 75 / 15
= 5 Seventh grade students per group