It seems that you have missed the necessary options for us to answer this question, but anyway, here is the answer.
Based on the given scenario above, the expression would be this:
a + c = 2904
12a + 6.5c = 27,126
Wherein a is for adult, and c is for children.
Here is the solution:
a + c = 2904
a = 2904 - c
Next,
12 (2904-c) + 6.5c = 27,126
34,848 - 12c + 6.5c = 27,126
-5.5c = 27,126 - 34, 848
-5.5c = - 7,722 (divide both sides by -5.5)
c = 1,404
Now going back to the first expression:
a + c = 2904
a + 1,404 = 2904
a = 2904 - 1,404
a = 1500
Hope this answer helps.
