To find the rate of change, put change in y over change in x. In order to first find the changes, you must subtract two y values from each other and two x values from each other, like this:
Change in y = 20-10
Change in x = 4-2
Then you can put these over each other:
20-10/4-2
Then simplify
20-10/4-2 = 10/2 = 5/1 = 5
So, this means the rate of change is 5. $5 per bushel.
If you also need part B it would be helpful to see the other chart because it's hard to understand in the writing you included. :) Comment and let me know if you post it so I can help you out!
