Answer :
Let number of adult tickets be a , therefore number of student ticket be a+4 .
And total cost of the tickets is 58, that is
[tex] 3.50a +2.50(a+4)=58 [/tex]
Distributing 2.50 on a+4
[tex] 3.50a+2.50a+10=58 [/tex]
Combining like terms
[tex] 6a=48 \\ a=8 [/tex]
Number of adult tickets are 8 and number of students tickets are 12.