I know for a positive fact that there's a picture in the book that goes along
with this question. I know that because the question talks about machines
that are "shown at the right".
What you have to understand is the reason for the picture. It's expensive to
print pictures in books, and if the picture were not necessary, then it wouldn't
be printed there.
It IS necessary, because you can't solve the problem, or even understand it,
without the picture. And that's why nobody here will be able to answer this
question for you. We don't even know what the two functions are, and those
make a BIG difference ! !