Answer:
Step-by-step explanation:
x = advance and y = same day
x + y = 70.......x = 70 - y
30x + 25y = 1950
30(70 - y) + 25y = 1950
2100 - 30y + 25y = 1950
-5y = 1950 - 2100
-5y = - 150
y = -150/-5
y = 30 <===== there were 30 same day tickets
x + y = 70
x + 30 = 70
x = 70 - 30
x = 40 <==== there were 40 advance tickets