Answer:
5
Step-by-step explanation:
You need to set up and solve a system of linear equations here.
Let s and a represent the number of students and adults respectively.
Then s + a = 9, and s = 9 - a.
Total ticket cost for the adults was ($8/adult)(a)
and for the students ($5/student)(s).
Total cost of the tickets was then ($8/adult)(a) + ($5/student)(s) = $60.
Then our system of linear equations is:
8a + 5s = 60
a + s = 9, or s = 9 - a. Substituting 9 - a for s, we get:
8a + 5(9 - a) = 60.
Then 8a + 45 - 5a = 60, or 3a = 15.
Solving for a, we get a = 5.
Solving for s using s = 9 - a, we get s = 9 - 5, or s = 4.
There were 5 adults in the group (and 4 students).
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