Solve this Riddle if you can

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ajttja
Gil-Gandel wrote:
FakeName6 wrote:

I want to revitalize this thread, so I will start with a variation of my first riddle. Here it is:

FakeName6 wrote:

Here is a probability problem of my own invention:

A man has a drawer with 150 socks: 50 red, 40 orange, 30 yellow, 20 green, and 10 blue. He takes six socks out. What is the chance that at least two of them are the same color?

 

My new one, unlike this earlier one (the answer was 100%, for those who missed it), is not a trick question. It involves real statistics. I am not totally sure that I got it right, so you guys might get me on it. Here it is:

 

The situation is the same as the first one. Except now you just pull two socks.

Simple, right? Or is it....


The chance of drawing a red sock followed by another red is (50/150) x (49/149). Add to that the chance of an orange followed by another orange (40/150) x (39/149). Add to that the chances of other-coloured pairs worked out similarly. The numerical answer is left as an exercise for the student.

.2389739 ect

LudRa95
ajttja wrote:
Gil-Gandel wrote:
FakeName6 wrote:

I want to revitalize this thread, so I will start with a variation of my first riddle. Here it is:

FakeName6 wrote:

Here is a probability problem of my own invention:

A man has a drawer with 150 socks: 50 red, 40 orange, 30 yellow, 20 green, and 10 blue. He takes six socks out. What is the chance that at least two of them are the same color?

 

My new one, unlike this earlier one (the answer was 100%, for those who missed it), is not a trick question. It involves real statistics. I am not totally sure that I got it right, so you guys might get me on it. Here it is:

 

The situation is the same as the first one. Except now you just pull two socks.

Simple, right? Or is it....


The chance of drawing a red sock followed by another red is (50/150) x (49/149). Add to that the chance of an orange followed by another orange (40/150) x (39/149). Add to that the chances of other-coloured pairs worked out similarly. The numerical answer is left as an exercise for the student.

.2389739 ect

"etc" is ambiguous. Wrong answer.

TheGrobe

That's irrational.

LudRa95

It's rational that "etc" is ambiguous in the context.

Gil-Gandel
TheGrobe wrote:

That's irrational.

No, the answer is certainly rational.

dogsix

[COMMENT DELETED]

sundog636

He didn't go anywhere because he stayed the 10 hours on his car

FakeName6

ajttja wrote:

Gil-Gandel wrote:

FakeName6 wrote:

I want to revitalize this thread, so I will start with a variation of my first riddle. Here it is:

FakeName6 wrote:

Here is a probability problem of my own invention:

A man has a drawer with 150 socks: 50 red, 40 orange, 30 yellow, 20 green, and 10 blue. He takes six socks out. What is the chance that at least two of them are the same color?

 

My new one, unlike this earlier one (the answer was 100%, for those who missed it), is not a trick question. It involves real statistics. I am not totally sure that I got it right, so you guys might get me on it. Here it is:

 

The situation is the same as the first one. Except now you just pull two socks.

Simple, right? Or is it....

The chance of drawing a red sock followed by another red is (50/150) x (49/149). Add to that the chance of an orange followed by another orange (40/150) x (39/149). Add to that the chances of other-coloured pairs worked out similarly. The numerical answer is left as an exercise for the student.

.2389739 ect

Yes this was what I got.

FakeName6

Good job ajttja and Gil-Gandel! And I'm glad you guys got the same thing as me. Pretty good for a 14-year-old?

Gil-Gandel
FakeName6 wrote:

Good job ajttja and Gil-Gandel! And I'm glad you guys got the same thing as me. Pretty good for a 14-year-old?

Yes, not really a riddle but a genuine piece of math.

An apothecary has a set of balance scales and the following weights: 1g, 3g, 9g and 27g. How many different weights can he weigh (clumsy sentence but I'm short of synonyms) with this equipment?

ajttja

i don't understand the question but i know there some reason the you have the weights being 3 to the 0, 3 to the first, 3squared,  and 3cubed so i get some credit.

LoekBergman

40

ajttja
[COMMENT DELETED]
TheGreatLlama

In Gil-Gandel's problem the answer is any integer up to 40g.  If it balances with the 1g, it is one gram.  If it balances on the same side as the 1g while opposite the 3g, it is 2g.  3 and 4 are obvious, 5 balances 9 on one side with the 1 and 3 on the other.  This can be followed for any number up to 40.  For example, if the weight is 32g, it will balance with 27g and 9g on the opposite side, and 3g and 1g on the same side

chesse_chames
[COMMENT DELETED]
chesse_chames
[COMMENT DELETED]
viper10091009

the sign said H p z u u l q l

Gil-Gandel

Nothing - signs can't talk.

Gil-Gandel
06-jwagg wrote:

In Gil-Gandel's problem the answer is any integer up to 40g.  If it balances with the 1g, it is one gram.  If it balances on the same side as the 1g while opposite the 3g, it is 2g.  3 and 4 are obvious, 5 balances 9 on one side with the 1 and 3 on the other.  This can be followed for any number up to 40.  For example, if the weight is 32g, it will balance with 27g and 9g on the opposite side, and 3g and 1g on the same side

Yes, and you can extend this indefinitely with powers of 3 (as ajttja realized).

LoekBergman
Gil-Gandel wrote:
06-jwagg wrote:

In Gil-Gandel's problem the answer is any integer up to 40g.  If it balances with the 1g, it is one gram.  If it balances on the same side as the 1g while opposite the 3g, it is 2g.  3 and 4 are obvious, 5 balances 9 on one side with the 1 and 3 on the other.  This can be followed for any number up to 40.  For example, if the weight is 32g, it will balance with 27g and 9g on the opposite side, and 3g and 1g on the same side

Yes, and you can extend this indefinitely with powers of 3 (as ajttja realized).

I repeat the correct answer: he can weigh 40 different weights. :-)

06-jwagg and ajttja gave the good explanations, though the wrong answers.