Given the graph we are asked to find the cost of one ticket. This can be seen below.
Explanation
From the graph, we can see that at the point when zero tickets had been sold, the students had raised 100 dollars. After one ticket was sold, the money increased to 125 dollars. Then after 2 tickets, it further increased by 25 dollars to 150 and so on so forth.
Therefore, we can say that the cost of one ticket is:
