I'm discussing this problem with a friend. We are discussing the first problem where the envelope is not opened, and we have the question as to whether the problem is well formed or not. Specifically the idea arose that it might not be well formed because the sample space does not contain explicit amounts.
I hope someone can reply to this with their views. I have another question but it depends on what I learn from the comments in the reply as maybe my question will be answered there.
Thanks for your consideration,