If you offered NO admissive chat or answered "I don't know, or no, I was within the posted range, then you stand a chance beating it in court. There are a couple of good websites that detail the means (which I don't have handy but google will probably find them) but then again, if your time's not worth it, just do the school...
An older woman told me recently that she was stopped by a state cop for speeding down the highway and the cop asked her if she knew how fast she was going and she said, "Around 100?" She was actually going around 90 and he let her go with just a warning. Cops like it when you don't lie to them.