Suppose x are the tickets sold for students (x >= 0)
Because 595 tickets were sold, so 595 - x will be the tickets sold for adults
=> x*1,5 + (595 - x)*5 = 1750
<=> 1,5x + 2975 -5x = 1750
<=> -3,5x = -1225
<=> x = 350
We have 595 - 350 = 245
In conclusion, 350 tickets were sold for students
And 245 tickets were sold for adults