A graph shows number of binders on the x-axis, from 0 to 10, and number of notebooks on the y-axis, from 0 to 10. A solid straight line has a negative slope and goes through (0, 10) and (5, 0). Everything to the left of the line is shaded. Eula needs to buy binders that cost $4 each and notebooks that cost $2 each. She has $20. The graph of the inequality 4x + 2y ≤ 20, which represents the situation, is shown. What is the greatest number of binders Eula can buy? What is the greatest number of notebooks Eula can buy? If Eula buys 7 notebooks, what is the greatest number of binders she can buy?