Problem Solving

Hi,

I did Math bin 4 (50 mins for 26 questions) from Princeton.
got 20 correct & 6 wrong.
3 wrong - probability
2 wrong DS- Geometry

How is the performance. Can any one update if I got 20 correct in Math Bin 4, which is supposed to be hard question, Am I doing good enough for a 48-51 in quant in the actual GMAT.

thanks
Ritz
PS: There was no careless mistake. It was pure unability to solve them. My guesses were not correct as well.