Answer:
375 Adult tickets
434 Student tickets
Explanation:
Let A and S be the numbers of Adult(A) and Student(S) tickets sold. We are told that A+S= 809.
We also learn that A + 59 = S [59 more student tickets sold than adult tickets]
Rearrange the last expression to isolate one of the two variables, A or S. I'll isolate A:
A = S - 59
Now use this expression for A in the first equation ("substitution").
A + S = 809
(S - 59) + S = 809
2S = 868
S = 434
From A + S = 809, we can find A:
A + S = 809
A + 434 = 809
A = 375
Check: Does 375 + 434 = 809?? YES
There were 375 Adult and 434 Student tickets sold, for a total of 809 tickets.