The points plotted in the coordinate plane represent the possible numbers of oranges and lemons that someone can buy in order to spend exactly $20.00 total on the two types of fruit. The price of each orange is the same and the price of each lemon is the same. The graph shows the number of oranges on the x-axis and the number of lemons on the y-axis, and the plotted points include $(0,20),(4,10),(6,5),$ and $(8,0)$. What is the price, in dollars, of 1 orange?