Answer:
<em>Total number of adult tickets sold = 10</em>
<em>Total Number of Students tickets sold = 30</em>
Step-by-step explanation:
Let  be the number of student tickets sold.
 be the number of student tickets sold.
Let  be the number of adult tickets sold.
 be the number of adult tickets sold.
As per the question statement, total tickets sold are 40.

Price of each student ticket = $5
Sales from students' tickets = Price of each students ticket  Number of students tickets sold
 Number of students tickets sold
Sales from student's tickets = 5 
Price of each adult ticket = $9
Sales from adult's tickets = Price of each adult's ticket  Number of adult tickets sold
 Number of adult tickets sold
Sales from student's tickets = 9 
Total sales is done by students and adult tickets is $240 as per the question statement.

Solving equations (1) and (2) using elimination method:
Equation  :
 :

Total number of adult tickets sold = 10
Putting  in equation (1):
 in equation (1):

Total number of students tickets sold = 30
<em>Total number of adult tickets sold = 10</em>
<em>Total Number of Students tickets sold = 30</em>