Answer: cost of advance ticket = $40
cost of same-day ticket = $35
Explanation:
# advance tix sold = 35
# same day tix sold = 20
a = cost of an advance ticket
s = cost of a same day ticket = $75 - a
35a + 20(75 - a) = 2100
35a + 1500 - 20a = 2100
15a = 2100 - 1500 = 600
a = 600/15 = 40
s = 75 - 40 = 35