In order to compare the two lengths, we first need to convert them both into the same units so we can compare them properly. To avoid decimal points, it would be easier in this case to convert the km to meters, which is the unit of the 200. 1km = 1000 meters, so 30km x 1000 = 30,000m
Out of 30,000m and 200m, the 30,000 is clearly greater so the one who traveled 30km is the one who has traveled further.
