Let’s solve this by identifying the unit rate. We can mark out what we know so far:
• 6 tutors are needed for every 72 students
• The part about the teachers is inserted to throw us off; we can disregard it
Given that information, we can set up equations:
6 tutors / 6 tutors = 1 tutor
72 students / 6 = 12 students
Our unit rate is 12; there is one tutor required for every 12 students.
Now that we have the unit rate, let’s multiply:
1 • 10 = 10
12 • 10 = 120
The academy needs 10 tutors for if it has 120 students.