I don't think we will see such Qs on GMAT..
You probably won't, but you have to admit that if you presuppose
that the two graphs won't look too difficult (as in the real GMAT),
then it's by far not as hard as it at first might look.
Even more, if you achieve to imagine what the two graphs look
like, it's quite trivial. In this case I intentionally chose those
"easy" relationship between the graphs, because the question
was designed to confuse most of you, but of course not all
By the way, 1:3 is correct.