We can determine the average number of tickets sold per student using the formula for average.
Here, let A represent the average tickets sold per child.
Let T denote the total tickets sold.
Let C stand for the overall number of children attending.
Based on the details provided in the question,
T=tickets1+tickets2+tickets3 and C=class1+class2+class3
Thus, A can be represented as:

The above formula represents the average number of tickets sold per child.