Well, technically, not every time, but I will share with you a method which ensures you win the game 96% of the time!
But before I get into the details of this strategy, for those of you who aren’t familiar with the game, Guess Who is a board game where you try to guess, from a selection of characters, which character your opponent has chosen.
You can ask a yes or no question to your opponent, and then use a process of elimination to remove characters and find your opponent’s character. For example, you might ask “Does your character wear glasses?” and if the opponent says “No”, then you can ignore all character who wear glasses.
The winner of the game is the first person to guess the opponent’s character.
So, there are two different strategies you can consider: more narrow guessing, and more broad guessing. If you take a narrower guess, like “Does your character wear hats?”, which has a 20% chance of being true, and the character does wear hats, then you’ve only got 5 characters left to consider (20% of 24 ≈ 5), out of the total 24 characters. If you take a broader guess which applies for 10 people, there’s a greater chance the answer will be yes. However, because it was a broader guess, you’re left with more people afterwards.
With the narrow guessing strategy, 1/24 times you will guess straight away, but 1/24 times you could also guess on your last go. (It’s out of 24 because there is a total of 24 characters). This means there is an equal chance of guessing it correctly on any number of your guesses, so on average there it will take 12 guesses to guess correctly.
If you asked the broadest questions possible, you could halve the amount of people you have to consider each time. So, you start with 24 characters, and after your first guess you have 12 left, after your second guess you have 6 left, after your third guess you have 3 left, and after your fourth guess you have 1 or 2 character left. If you have 2 characters left after your fourth guess, you need to take another guess to narrow it to 1 character. Therefore, you have a maximum of 5 guesses you need to make in order to win.
5 guesses is a lot less than 12, so the broader questions mean you are more likely to win – but this is only in the case where you halve the characters in the game each time.
All of the characters in “Guess Who” can be sectioned into groups of 5: 5 have glasses, 5 have moustaches, 5 have red hair, 5 have hats, 5 have blue eyes, 5 are bald, and there are many more.
Groups in Guess Who (Image credits: Mark Rober)
It therefore may seem a bit tricky to halve the characters each time, but there are multiple methods you can use to make sure this happens.
You could ask a question like “Does your person have white hair or red hair or glasses?”
You could equally ask “Does your person’s name start with the letters A to L?”
This method has been shown to mean that players win “Guess Who” 96% of the time by Mark Rober, a YouTube Engineer. You can see exactly how he calculates this probability, and how he established these strategies for winning in the following video.
Comments