6. The middle school is taking a field trip to the art museum. Chaperones
are needed. Grade 6 has 54 students; grade 7 has 63 students; grade 8
has 72 students. Teachers want to assign chaperones to smaller groups
of equal size, but do not want these groups to mix students from
different grades.
a. What is the greatest number of students in each group?
b. How many groups of students will there be from each grade?
c. Teachers must reserve lunchrooms at the museum, and each
lunchroom is large enough to hold 5 groups of students. (It is
possible for students in different grades to eat together.) What is
the least number of lunchrooms that must be reserved?