Let
x = number of tickets
y = cost
For each row, divide the cost over the number of tickets
Row one: y/x = 3/2 = 1.5
Row two: y/x = 6/4 = 1.5
Row three: y/x = 9/6 = 1.5
Row four: y/x = 12/8 = 1.5
Row five: y/x = 15/10 = 1.5
The constant of proportionality is 1.5
This means each ticket costs $1.50
