:dubious: Since when? Not in any statement of the puzzle I’ve seen - though in all those it’s made clear that he’s not going to ever open the car’s door (or the door you picked, for that matter).
If Monty could pick the door with the car and then start pointing and laughing at you for not picking the winner, then yeah, switching to the other loser door won’t help you.
Since always. Have you ever even seen the show? The puzzle always specifies that the player may stick with the original choice or switch to the other unopened door.
Wikipedia version
Marilyn’s site
Better Explained
Wolfram
Scientific American
Rosenhouse, Jason, The Monty Hall Problem, Oxford Press, 2009, p. ix
And they also specify he ain’t gonna open the door with the car. If you’re going to change the problem so far to allow that as a possibility, then there’s no reason to assume that the phrasing that assumes you would never want to pick the opened door was actually a rule preventing it.
Suffice to say if Monty can go around opening the car door whenever possible so he could mock you for not literally tackling him and stopping him from doing so, it changes the problem significantly. If he demonstrates a marked tendency for doing this, then you should clearly not switch, because the fact he didn’t mock you with the car suggests he couldn’t because you already had picked it. (Unless he’s allowed to open your door too, in which case you’re boned in all cases.)
Actually, if you read Mr Shine’s spoilered answer, it’s pretty clear that he did not intend his version to be the same as the classic Monty Hall problem, though you’re maybe supposed to think it is.
In Mr Shine’s version, if your original choice had had a goat, “the man” would not have offered to let you switch.
For the record, I don’t like Mr Shine’s version of the question. If “the man” is that self-serving, why is he offering you the chance to win a car in the first place?
The phrasing says you have the option to switch to the other unopened door. That’s actually a rule. In six cites.
Tell you what - I’ll concede that the situation could, if you massively alter the problem in one specific way and then carefully avoid altering it in another way, become a significantly more stupid situation than it’s generally conceived.
I think that’s a reasonable description of what we’re discussing here.
One that my father heard from one of his students:
Technically the answer is very simple. In retrospect, it’s even obvious. But every* person I’ve told this to has given up, then done a massive :smack: when I told them the answer. I gave up in a math-panic, then felt really stupid when my dad told me the answer. My father, who takes advanced mathematics courses for fun, had to have the student tell him the answer.
*As I was writing this, my brother just became the only person so far to get it, and on the first try, too. Whadaya know.
Always heard that one with the question being how old the bus driver is. Traps people who don’t think about what numbers actually mean in a problem.
The version I heard, which is more or less the same math riddle though whose answer is slightly less obvious, goes something like this:
A certain thing can spontaneously reproduce once a day; starting with one it will take 30 days to reach 536,870,912 things. How many days would it take to reach that total if you started with two things?
Like with your riddle most people mistakenly say 15 days or half the time, however the answer is: 29 days. In the case where you started with one thing, after one day you have two things and equaled the starting condition of the riddle.
Wait, what?
In terms of percent-solids rather than percent-water, the potatoes were 1% solids before and are 2% solids after. 1% is 1/100, and 2% is 1/50.
Thanks, yea I just wasn’t seeing it. I had to get out paper and do it like this:
total weight (y) = potato weight (p) + water weight (w)
p = 1
w = .98y
y=p+w
y=1 + .98y
y-.98y = 1
.02y = 1
.02y/.02 = 1/.02
y = 50
I simply wasn’t seeing it until I really dumbed it down…
Part of what I left out was
RAY: Now you can solve this puzzler algebraically, and if you don’t solve it algebraically, you are going to get the wrong answer.
I gotta say that even knowing how it works it’s still really unintuitive. But then fractions/percentages are always weird.
B is 50% more than A.
A is 2/3 of B.
I think I would answer S-E-W for the first spelling quiz.
There was an episode of CSI where Nick asked Gil why he didn’t get the promotion to CSI III.
Gil Grissom: Repeat after me. Silk, silk, silk.
Nick Stokes: Silk, silk, silk.
Gil Grissom: What do cows drink?
Nick Stokes: Milk.
Gil Grissom: Cows drink water. They give milk.
[Later]
Nick Stokes: Hey, Catherine, say, “Silk, silk, silk.”
Catherine Willows: Silk, silk, silk.
Nick Stokes: What do cows drink?
Catherine Willows: Water. Why?
Nick Stokes: [after a disappointed pause] Never mind…
Followed by “Faux” and “Know”.