The slope of the lines represent the runners' speeds. Therefore, the purple line represents Jerry, since he started off faster but also stopped in the middle, and the slope became 0 (horizontal portion of the line.)
The red one represents Katja because she started and ended at a constant pace, which is visible in the red line's constant slope.
The answer I got is 17x-70/5
The answer i came up with is 0.68 i don't know if thats what you need or not. hopefully i helped.
