I think you explain it very well!

So the thing is something like the following, right?: "Looking at it from the outside, a world where 21 heads showed in a row is incredibly unlikely: (if the coin is fair) I would happily bet against this world happening. However, I am already in an incredibly weird world where 20 heads have shown in a row, and another heads only makes it a bit more weird, so I don't know what to bet, heads or tails."

So, what was the answer given in the course?

Just to add, this thread of Phil Metzger argues otherwise:

https://twitter.com/DrPhiltill/status/1583106346538311680

I love to listen to stuff. Books, articles, podcasts, music, radio... But I must warn the audience that modern life leaves us very few opportunities for mind-wander, and that listening to articles/books while doing chores, commuting, exercising, etc. diminishes these even further. So be mindful of this and try freeing some time for you to wander / not concentrate in anything.

To read a website in your computer (blog post, news article, etc):

• If you use Firefox, the built-in tool "Reader view" (you can access it pressing F9 or clicking a small Written-paper-icon at the right-most side of the url bar, left of the Bookmarking star) has an option to listen to the text. You can control the speed (up to a point, it does not allow to speed it up enough, in my view) and the voice. It is not awesome, but for the standards of the (free) text-to-speech options, I find it good and used it very often. A very useful plus of the Reader view is that it indicates the approximate time one would need to read the text.
• If you use Chrome, you can download an extension called Reader View. It basically does the same than the Firefox Reader View (and it looks very similar as well, I actually believe that it is deliberate). There are other extensions offering more or less the same. I settled for this one because it also indicates the approximate time one needs to read the text.

Reading PDFs with headers/footers:

• Every app I tried suck at reading PDFs with headers/footers! I have not found a way to make the reader ignore them. However, there is an hilarious workaround: open the pdf file with MS Word and use the in-built tool to read the text. It takes a while for word to open long pdfs, but Words "understands" the pdf's headers and footers (it formats them as headers/footers in word), and the reading tool do not read them. 

All these are not perfect but alright in my opinion. However, listening to (or reading+listening to) a text with too many citations is very tedious. (Free) readers do not handle them well. They read them with a very weird and slow pace.

How can you read 2-3x faster than a person speaks (1x)? Do you mean that when you "read" you just skim most of the time and really read only the parts you are interested in?

As others mention, most readers allow you to increase the speed of the the audio. Up to 2x, for light content and with headphones is usually alright if you can concentrate on the audio. Faster than that, I find it really difficult to follow, so you are probably still faster.

I'm always curious to understand how people with very low confidence can end up doing such amazing stuff or in very high positions in organisations. How do you even think in going for it? (I know it is a very personal question. Please, don't feel obliged to answer!)

For completeness, I would add another (more general) Possible action:

develop a system that is able to investigate, develop and provide such cheap (probably not-patentable) treatments, therapies or improvements in general that are currently not pursued because they are not expected to be profitable.

(I know, much easier said that done!)

We want our farm animals to eat a lot...

What we "want" is that farm animals grow fast and big, not that they eat a lot. Actually we want them to eat the least possible and grow fast and big.

My idea so far is to use a spreadsheet set to something similar to this:

where the cells are checkboxes and the erased text would include different chores, types of work tasks/projects, and entries such as commuting, sleeping, eating... probably I would also include hobbies or something similar to "other fun", "other productive", "time wasted". Then it automatically counts how many boxes are checked for each column and so tells me how much time I spent in each task/chore/etc.

However, I am really not sure if this is going to be useful in the long run. I think that this degree of detail will be very useful at the beginning to get a sense of how much time I spend in all aspects of my life, but probably in the long run it makes more sense to track work time? Does this seem like a reasonable method? Any feedback is welcome, thanks.