Step-by-step explanation:
well, you must have some additional graphs (coordinate grids with lines going across them (probably in two different colors or patterns - one for Mary, one for Kim), while the horizontal x-axis is most likely for time (and there should be segments called A, B and C), while the vertical y-axis is most likely for the distance the riders were going.
we don't see this information. but I can try to give you some general guidance.
now you need to check these lines that go across the grid.
the higher up a point of a line is, the more distance a rider was adding to her ride at that point of time, meaning the higher the speed of that particular rider at that very moment. and the lower the point, ..., well you get it, right ?
now based on these lines you can answer the questions yourself.
when you follow the line for Mary, for example, in what segment of the x-axis (time) is the line the highest (she was riding fastest) or the lowest (she was riding the slowest)? maybe it is only for a part (or even only a few points) of the line in that interval.
when a rider stopped, guess what distance the rider was traveling while stopping ? exactly, 0. so, when a driver stopped, you will see the corresponding line go just flat parallel to the the x-axis for the period of time of stopping.
and you find the rider that lives 0.7 miles from school by seeing that the line goes flat parallel to the x-axis at y = 0.7 miles, and stays flat probably until the end of the chart.
