Answer: 532
Step-by-step explanation:
Let x be the number of students and y be the number of non-students.
Then, by considering the given information, we have
[tex]x+y=817-----(1)\\\\2x+3y=1919-----------(2)[/tex]
Multiply 2 on the both sides of equation (1), we get
[tex]2x+2y=1634--------(3)[/tex]
Subtract (3) from (2), we get
[tex]y=285[/tex]
Put the value of y in (1), we get
[tex]x+285=817\\\\\Rightarrow\ x=817-285=532[/tex]
Hence, 532 student tickets were sold .