An interesting math riddle

yes it is to your advantage to switchchikinlad

whats the advantage? in % chance

I'm probably wrong, but I don't think it would be, because with one of the doors revealed, you now have a 50/50 chance of picking the right door.Legendaryscmt

I remember this riddle, it's always in your advantage to switch doors.bededog

That can't be right :evil:.

Care to explain?

you switch and heres why....when you orignally pick you have a 1/3 chance of picking it right.2/3 times your wrong,now when he narrows it down to 2 most people think the odds improve to 1/2 but they are mistaken.when you switch you are saying that your first guess is wrong which is true 2/3 of the time.lazzordude

No, if you switch, your chances become 1/2, not 2/3.

you switch and heres why....when you orignally pick you have a 1/3 chance of picking it right.2/3 times your wrong,now when he narrows it down to 2 most people think the odds improve to 1/2 but they are mistaken.when you switch you are saying that your first guess is wrong which is true 2/3 of the time.lazzordude

Lol wut?

Dude... you have two doors left... the car is behind one of the two.

Your first guess is irrelevant:|

you switch and heres why....when you orignally pick you have a 1/3 chance of picking it right.2/3 times your wrong,now when he narrows it down to 2 most people think the odds improve to 1/2 but they are mistaken.when you switch you are saying that your first guess is wrong which is true 2/3 of the time.lazzordude

Here is the Wikipedia entry for it if anyone's interested. II-FBIsniper-II

That is wrong

I'm probably wrong, but I don't think it would be, because with one of the doors revealed, you now have a 50/50 chance of picking the right door.Legendaryscmt

that's what i was thinking.

[QUOTE="lazzordude"]you switch and heres why....when you orignally pick you have a 1/3 chance of picking it right.2/3 times your wrong,now when he narrows it down to 2 most people think the odds improve to 1/2 but they are mistaken.when you switch you are saying that your first guess is wrong which is true 2/3 of the time.chessmaster1989

Lol wut?

Dude... you have two doors left... the car is behind one of the two.

Your first guess is irrelevant:|

[QUOTE="chessmaster1989"]

[QUOTE="lazzordude"]you switch and heres why....when you orignally pick you have a 1/3 chance of picking it right.2/3 times your wrong,now when he narrows it down to 2 most people think the odds improve to 1/2 but they are mistaken.when you switch you are saying that your first guess is wrong which is true 2/3 of the time.lazzordude

Lol wut?

Dude... you have two doors left... the car is behind one of the two.

Your first guess is irrelevant:|

It's not 66%. The overal chance of winning the car if you switch doors is 50%. If you don't it's 33%. I made a simple program to simulate that and run it 1000 times.

[QUOTE="lazzordude"][QUOTE="chessmaster1989"]

Lol wut?

Dude... you have two doors left... the car is behind one of the two.

Your first guess is irrelevant:|

Lokantis

It's not 66%. The overal chance of winning the car if you switch doors is 50%. If you don't it's 33%. I made a simple program to simulate that and run it 1000 times.

[QUOTE="Lokantis"][QUOTE="lazzordude"]no its not,you only had a 33% chance of picking it right on the first try...therefore when the host eleminates a wrong choice your left with your original pick and 1 remaining choice.you are essentually picking if you think your first choice is right or wrong.for a new car would you take a 33% or a 66% chance of winning?thats why you switchlazzordude

It's not 66%. The overal chance of winning the car if you switch doors is 50%. If you don't it's 33%. I made a simple program to simulate that and run it 1000 times.

Maybe try to simulate it with playing cards and see for yourself?

and its not "the other 33%", its 17% which represents the case where your first choice is the door with car AND you don't switch

[QUOTE="Lokantis"][QUOTE="lazzordude"]no its not,you only had a 33% chance of picking it right on the first try...therefore when the host eleminates a wrong choice your left with your original pick and 1 remaining choice.you are essentually picking if you think your first choice is right or wrong.for a new car would you take a 33% or a 66% chance of winning?thats why you switchlazzordude

It's not 66%. The overal chance of winning the car if you switch doors is 50%. If you don't it's 33%. I made a simple program to simulate that and run it 1000 times.

:lol: math fail

[QUOTE="lazzordude"][QUOTE="Lokantis"]

It's not 66%. The overal chance of winning the car if you switch doors is 50%. If you don't it's 33%. I made a simple program to simulate that and run it 1000 times.

Lokantis

Maybe try to simulate it with playing cards and see for yourself?

and its not "the other 33%", its 17% which represents the case where your first choice is the door with car AND you don't switch

[QUOTE="lazzordude"][QUOTE="Lokantis"]

It's not 66%. The overal chance of winning the car if you switch doors is 50%. If you don't it's 33%. I made a simple program to simulate that and run it 1000 times.

chessmaster1989

:lol: math fail

[QUOTE="chessmaster1989"][QUOTE="lazzordude"]so your saying if you switch its 50% but if you dont its 33%,well where did the other 33% go?see your math is flawedlazzordude

:lol: math fail

:P

I still say it's 50-50...

I've never been good at these kinds of puzzles, though, even though I'm good at math :P.

[QUOTE="lazzordude"][QUOTE="chessmaster1989"]

:lol: math fail

chessmaster1989

:P

I still say it's 50-50...

I've never been good at these kinds of puzzles, though, even though I'm good at math :P.

[QUOTE="chessmaster1989"][QUOTE="lazzordude"]oopsies,i typed 33 instead of 17 for some reason.lol but its a funny typo so its all cool.lazzordude

:P

I still say it's 50-50...

I've never been good at these kinds of puzzles, though, even though I'm good at math :P.

That no make sense... :(

[QUOTE="lazzordude"][QUOTE="chessmaster1989"]

:P

I still say it's 50-50...

I've never been good at these kinds of puzzles, though, even though I'm good at math :P.

chessmaster1989

That no make sense... :(

[QUOTE="chessmaster1989"][QUOTE="lazzordude"]okay,lets forget the exact percentages for a second....i think we all think your better off switchinglazzordude

That no make sense... :(

You has same odds :P

This is a really weird one at face value, but it can be explained as follows:

First, you select a door. You have no idea whether or not it is right. Now, there are two options: either you selected correctly (probability 1/3) or you selected incorrectly (probability 2/3).

A door is opened to reveal a goat. Now, consider the situation where you did not select correctly. You then have a 100% chance of getting it right if you switch, since the host opened the other incorrect door. However, if you did select correctly, then you have a 0% chance of getting it right if you switch.

But, you had a 2/3 chance of getting it wrong the first time. Therefore, you also have a 2/3 chance of getting it right if you switch, since you will always get it right if you switch and you initially had it wrong.

This is a really weird one at face value, but it can be explained as follows:

First, you select a door. You have no idea whether or not it is right. Now, there are two options: either you selected correctly (probability 1/3) or you selected incorrectly (probability 2/3).

A door is opened to reveal a goat. Now, consider the situation where you did not select correctly. You then have a 100% chance of getting it right if you switch, since the host opened the other incorrect door. However, if you did select correctly, then you have a 0% chance of getting it right if you switch.

But, you had a 2/3 chance of getting it wrong the first time. Therefore, you also have a 2/3 chance of getting it right if you switch, since you will always get it right if you switch and you initially had it wrong.

GabuEx

But, the probabilities shift when you open the door. After that, there are two possible doors, and the third is irrelevant. Since there is one of the two objects behind each, there is a 50-50 chance of one of the objects being behind the door.

Your explanation just uses some convoluted mathematical logic that, quite frankly, does not seem to work...

But, the probabilities shift when you open the door. After that, there are two possible doors, and the third is irrelevant. Since there is one of the two objects behind each, there is a 50-50 chance of one of the objects being behind the door.

Your explanation just uses some convoluted mathematical logic that, quite frankly, does not seem to work...

chessmaster1989

Out of curiosity, and partly to prove it to myself, I wrote a computer simulation of 2,000,000 trial runs with both the door choice and correct door picked at random. In the first 1,000,000, the simulation stays with the door it initially picked, and in the second 1,000,000, it switches to the other unopened door. The results:

Conclusion: probability is indeed 2/3 if you switch.

Again, this hinges on the fact that the host will always open a wrong door. If the host opened the door completely at random, you would be correct, as in that case you could have the situation where if you picked wrong the first time then it'd be impossible for you to win.

There are many more math riddles. The world is full of mysteries, does it not?

"Infinite in mystery is the gift of the goddess
We seek it thus and take it to the skies
Ripples form on the water's surface
The wandering soul knows no rest"