Answer: 85 student tickets, 65 adult tickets.
Let's say the # of students is x and the # of adults is y. The two equations we get are 7.50x + 15y = 1612.50 and x + y = 150
x = 150 - y
7.5(150-y) + 15y = 1612.5
1125-7.5y+15y=1612.5
7.5y=487.5
y=65
x=150-65
x=85
Hope this helps!