Kathleen A. answered 01/08/20
Math teacher with degree in Mathematics
When you have two unknowns (advanced tickets and same day tickets) you must create two equations and solve the system.
the cost equation is 30a+25s=975
the ticket equation a+s=35
The quickest way to solve this is by substitution
Solve for “a” or “s” in the second equation. I will solve for “a” which is a=35-s
Plug in
30(35-s)+25s=975
1050-30s+25s=975
1050-5s=975
1050-975=5s
75=5s
s=15
Then plug in 15 for s in the original equation a+s=34 or a=35-s then a=20
20 advance tickets
15 same day tickets