Answer:
512 student tickets were purchased.
Explanation:
Represenation of the unknowns: Let s be the number of student tickets and a the number of adult tickets. Then s + a = 1294.
The dollar amounts are thus ($5/ticket)s + (8/ticket)a = $8816.
Goal: Find s; to do this, eliminate a.
Since s + a = 1294, a = 1294 - s
Then: 5s + 8(1294 - s) = 8816, or
5s - 8s + 8(1294) = 8816, or
-3s + 10352 = 8816
Isolating the 3s term, we get
-3s - 1536 = 0, or
3s = 1536, which yields s = 512
512 student tickets were purchased.