Essentially what we have here are two points that we can use to find the slope for a line for the amount that Jeremy earns based on the number of games.
The two points that we have are: (4, 140) and (6, 210).
So we know that slope is represented by the equation:

Then, if we assign the point (4, 140) as the "1" values, and (6, 210) as the "2" values, we can plug those values in to get the slope:

Therefore, by using this equation, the slope of the line based on Jeremy's pay based on the number of games they referee is
35.