You have a $20 bill, and you need to double it. You have 1 month, you must keep it in cash (No banks, cashapp, credit cards), you don’t have an address, a phone number, or and you can’t interact to people in public. using just the internet and an email, how do you double the money?
I want to add that I know this sounds mean like I’m angry, but it’s kind of more like I’m frustrated with the impossible constraints of the mental exercise.
If I have offended you, I do apologize. It’s not my intent.
I enjoy solving puzzles, but assuming that none of your constraints can bend, then the only thing I can think of would be for you to send out a mailing list begging for money and hope that enough people respond, like a letter saying, “hey, send me a dollar and you’ll get good luck”, or something.
For $20, you should be able to send about 40 letters, and if all 40 of them send you $1, then that would meet your requirements.