So Wrong

My econometrics professor:
"I gave you a lot of homework problems, and that should give you enough to work on to prepare for the final. I don't expect anyone to be able to finish all of them, though..."

I hate this! How am I supposed to know which problems are the ones that are too hard for me to actually complete and which ones I need to know but are just giving me trouble?

and

"I sent out an email with some hints and answers for some of them, but I don't know the answers to all of them."

Dre, can I donate my brain to science? It seems like the most reasonable option at this point.