In University we had a management class, where we were supposed to answer 10 questions such as:

1. What percentage of bronze is typically made of copper?
2. How many countries have at least one McDonald’s?
3. How many employees did ebay have in the first quarter of 2006?

The goal was similar to your exercise. Then we were told to pick two numbers, alower number and a higher number. You must be 95 % sure that the correct value lies in between this range. So lets tackle the first question:
My minimum guess would be 65% and my maximum would be 95%. In reality 92% of bronze is made out of copper, but its very unlikely you know this. Therefore you also have to estimate a range where you feel confident that the true value lies in between. Great exercise for me and you keep getting better at this. If you want to further read about it, here’s a whole book about it:https://www.howtomeasureanything.com/3rd-edition/

Thanks for your article!