Use 8/10 and 10/12. This represents how many spring rolls over how many minutes. Make your equations like this: 8/10 = 40/x and 10/12 = 40/x. Find x, which will give you the minutes it takes them to make 40 rolls.
You get x = 50 for the first one and x = 48 for the second. Nora makes 40 rolls in 50 minutes, and Eli makes 40 rolls in 48 minutes. Eli is faster.
You have your x and y values and if you substitute them in you find yourself with 40 - 20 = 24 this doesn't make sense. So you get another answer which can be set to 20 and 40 - 20 = 20 therefore you you can make sure that your line intersects with your x and y values.
