It varies. Many of them are designed to be too hard for you to complete in the allowed time (they want to see your problem solving and how far you get). Others can be solved many ways and they want to see how good of a solution you come up with.
Ok. This one is also timed. Max time is 135 minutes per test. Another reason im nervous
Just do your best and try not to panic.
Just do your best. Accept that before hand that you will make some mistakes and there will be some things you won’t be sure about. That’s OK - they’re not looking for perfection,
Just breathe and try to relax. You’re either ready for the job or you aren’t. If you don’t get this one, then this will be a learning experience that will help you down the like. I’ve done a few of these things and every one has made me a better coder in some way, teaching me something or pointing out a weakness.