The only correct answer is that you are in the SAME position you were before you passed the LAST place racer.

If you were in first place and passed last place you are still first, but last has gone a lap down.

If you were in tenth place when you passed last place you are STILL tenth and the racer in last plae is still last and still a lap down.

And, if you pass the last place racer again you are still in the same position you were before the pass, and that racer in last has gone down another lap...

George