Hello, Alyssa,
We have two unknowns: the numbers of student (S) and adult (A) tickets, So we'll need at least two equations.
We can say that S + A - 125, the total numbr of tickets sold.
We can also set up an expression that amounts to the total sales of $850 by adding 6*S to 8.5*A:
6S + 8.5A = 850
Rearrange the first equation to solve for S(or A, if you'd like):
S = 125 - A
Then substitute this value of S into the second equation:
6(125-A) +8.5A = 950
750 - 6A +8.5A = 950
2.5A = 200
A = 80
Now we can find S: 80 + S = 125
S = 45
Check to see if these work:
6S + 8.5A = 950
6(45) + 8.5(80) = ?
= 950 - it works.
Student 45 tickets
Adult 80 tickets
I hope this helps,
Bob