The picture isn’t clear enough
I think there's supposed to be a picture here. Anyway, you can find out by finding the slope of the line on the graph and comparing it to .5 which is Henry's slope. If the graphed slope is larger than .5 then Clark hikes faster, if it is less than .5, Henry hikes faster.
Hope this helps :)
No
because the number of cups of vegetable soup is greater than the number of cups of stock