Tactics trainer tactics

Hi. I'm new to chess.com, still working my way through all the great stuff on this site.

Can someone explain the scoring method on tactics trainer to me? I notice that the green bar diminishes, then when it disappears there's a short period of time before the red bar appears and your rating starts to go down.

I have no questions about CORRECT answers, but if you can't see the solution is it best to

1. Make a stab at the answer before the green bar disappears

2. Make a stab at the answer before the red bar disappears

3. Attempt no answer. Just hit the "solution" button.

Oh, and I don't really understand what the percentage is all about. Is that the percentage of participants who get the answer correct?

Forgive me if the answers to these questions are already on the site. This site is huge and I've just explored a small percentage so far.

Personally, I don't worry about the time on  tactics trainer, I just try to discover the puzzle, or find the answer to the position, it's all about helping you get better at tactics, and the timer is just one of those things that encourages you to find it as fast as possible.  So attempt to find the position answer as fast as possible but don't worry abotu the affect on your ratings, it should help you regardless.  Be sure to click the solution button if you get it wrong, or continue to try the position over and over until you get it, you really should get the answer by your means or the solution button help understand the problem.

Thanks Rookbuster. Greetings from the Great White North. I agree that Tactics trainer is definitely helping my game, but the answers I get wrong seem to put me further back than the correct answers push me forward.

I'm looking for a way to minimise the loss when I can't find the solution in time.

(Almost invariably I find the solution 10 seconds after the clock has expired. (Darn))