Question 1039952
Assign variables to how many of each ticket.
Account for the number of tickets sold.
Solve for each variable.


Your description means this:
x, the number of student tickets
y, the number of adult tickets
T, the total number of tickets sold
x=2y
x+y=T
2y+y=T
3y=T  or  y=T/3



That is all that you can do.  Information is missing from your description.