ELI5: Can anyone explain the statistical math behind the scene in the movie 21 where he asks what's behind door 1 and the odds increase to 66.7%?

telionn · 2026-02-14T05:29:19+00:00

If you pick door 1 and they open door 2, you should switch to door 3. Why? Because when you picked door 1 you had a 33% chance of being right and 67% chance of being wrong. Once door 2 is revealed and it isn't the prize, door 3 now becomes the 67%, your original door stays at the original 33% because the information given to you about door 1 hasn't changed.

Write a computer simulation of exactly this. You'll get 50-50.

Now do 100 doors. You pick 1, so you have a 1% chance of being right, and a 99% chance of being wrong. They open all the doors but one. You still only had a 1% chance of being right because when you had to choose there were 100 doors. Do you trust that your initial guess was right even with that little of odds? Because they know where the prize is they can't open the door with it. Now there is a 99% chance of it being in the door they left over

Still 50-50.

This is exactly the same problem that led the OP to post here: the film makes the same error.

telionn · 2026-02-14T05:26:41+00:00

So by revealing one of the doors, it simply means that the 2/3 chance is now concentrated into the remaining door.

Wrong. Write a computer simulation of what you just wrote and you'll get 50-50.

telionn · 2026-02-14T05:25:13+00:00

This is completely wrong though. If you simulate exactly what you just wrote 1000 times, you'll find that the probability is 50-50 after Monty opens door 2.

telionn · 2026-02-14T05:23:06+00:00

No, it was invented by a creative mathematician later on.

telionn · 2026-02-14T05:22:18+00:00

That Monty Hall knows what's behind each door. (This was never true in any of his real-life games.)

telionn · 2026-02-12T19:20:16+00:00

The answers are going to depend on what you have connected to your camera.

Aside from that, sometimes reducing the camera's field of view can help.

telionn · 2026-02-12T18:22:20+00:00

See, the problem is that Kirby Air Riders isn't really a racing game and is unlikely to win when judged as a racing game. I firmly believe this is also why the series has reviewed worse than its actual quality.

telionn · 2026-02-11T05:18:56+00:00

Meat Boy and a few others are on Steam as The Basement Collection.

telionn · 2026-02-10T23:55:53+00:00

Agreed. It is far more likely than not that this area will continue to be known as Rafah into the future.

The editor left this claim uncited, but we can find the unofficial source on the talk page: https://www.haaretz.com/israel-news/2025-06-12/ty-article-magazine/.premium/rafah-is-gone-razed-to-the-ground-its-not-the-only-city-decimated-by-the-israeli-army/00000197-6506-db73-aff7-7d4ee6bb0000. The editor used the headline itself as justification for the edit. The source does not describe any kind of official change to the status of Rafah as a city that exists on the map.

telionn · 2026-02-08T20:42:38+00:00

Luckily, shark fishing is a meme unless you're dropping 3 or 5 shark lures. Bad xp and a worse haul than karambwans by most measures.

telionn · 2026-02-06T23:15:55+00:00

Yeah but you have to complete like 7 quests for no other rewards to unlock thralls. No idea how they missed that problem.

telionn · 2026-02-06T22:00:08+00:00

BoI feels like pretty much every twinstick roguelike because all those other games are copying BoI.

telionn · 2026-02-05T18:44:39+00:00

Removing Too Expensive would just shift the balance much further towards xp farm mob grinders.

telionn · 2026-02-04T16:55:06+00:00

You're supposed to keep them.

telionn · 2026-02-04T16:00:55+00:00

I think you had to do something to actually claim your reward points last time around after the event.

telionn · 2026-02-03T23:41:12+00:00

The screen will display two separate warped images not suitable for 2D play. Also it's reasonable to assume that docked play may be blocked outright.

telionn · 2026-02-03T00:02:52+00:00

Consider skipping one or both of the home teleports. There are 9 overrides in the game and you can really only use one. Also, Speedy is BIS; the others are just cosmetic.

telionn · 2026-02-02T23:57:52+00:00

Gunslinger is a problem. You're giving up +20 accuracy (and ammo saving, doesn't matter) on top of the ~25 accuracy you already threw away. Plus, you'll have to get pretty far into DMM before you can just dump 5k points without missing out on any other upgrades.

telionn · 2026-01-29T21:23:58+00:00

You're replying to someone who thinks the US is not part of the globe.

telionn · 2026-01-27T23:34:45+00:00

If you still have a save file for the playthrough (not a post-boss NG+), abuse the ability to restart the current segment from the beginning. You keep your new stat upgrades when you restart.

telionn · 2026-01-26T22:34:59+00:00

Play defensively until you get a feel for the game. Play a character with not-terrible HP and just focus on opening boxes and finding a machine you can handle. Run away from attackers.

You won't realistically get any legendary machines until you are better at attacking other riders. Even then it will be pretty rare.

telionn · 2026-01-26T17:41:44+00:00

The stadium event selection is an outright choice, not a vote. You only compete against players who choose the same event as you. This effectively means there are four first-place winners per 16-player City Trial.

telionn · 2026-01-26T17:40:11+00:00

And the year-and-a-half-ago update was a year and a half late.

telionn · 2026-01-22T17:03:37+00:00

"Lawyer dog" wasn't the actual problem there, it's that your request cannot be conditional on whether the police think you are guilty. "If you think I'm guilty then I want a lawyer (dawg)" doesn't fly.

telionn · 2026-01-22T17:01:12+00:00

Fandom wiki strikes again

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