Probability - How does it work?!

Brilliant idea. I neve thought of that. Also, and this is something that I have really struggled to understand and still don't is this scenario.

You have 3 cards lying face down and on one of them is an X meaning win and you are asked to pick one card. If one of the two cards you did not choose is turned over reveals it to be blank, so you still have a chance of winning. If you are then offered the chance to swap your original choice for the other remaining card. You should swap as this increases your chance of winning. This is a headfuck and I think it is related to 'The Envelope Paradox'

This is also known as the Monty Hall problem. Easiest way to figure it out is to imagine there are 1000 cards. Imagine you picked one (1/1000 chance of getting the right one) and then 998 of the others were turned over. The person won't turn over the X card as he knows were it is, so there is now a 1/1000 chance your card is correct, and a 999/1000 chance that the other remaining card is; hence you should swap.