Question 1107515
This can't work to make $2995 in sales for 279 adult tickets (the maximum), because that would net $1395 only.  Accordingly, I edited the question to make the total sales $995.
Adult tickets=A
Student tickets=S
A+S=279
5A+3S=995
-5A-5S=-1395, multiplying the top by -5
-2S=-400
S=200 students or $600 total
A=79 adults or $395 total