In total 530 tickets
Students tickets cost $3
Adult tickets cost $4
in total receipts were $1740
x= students
y=adults
we can have the next two equations
x+y=530
3x+4y=1740
we can rewrite the first equation
x=530-y
we substitute the equation above in the second equation
then we substitute the value of y in x=530-y
In total 380 students attended the talent show