GMAT Strategy

Hi,

is there a resource, where I can find categorized questions?
For example I want to learn only the questions where one car is faster or the other train overtakes the car etc.

Or only the questions with X earns two times more than Y, how much etc.

I want to concentrate on one sort of questions - not do them all mixed up.
Is there a resource for that approach?

Thank you in advance.
Bye, Chris

Does nobody know a resource of math problems that are categorized?