Can You Solve the Mystery of the Tape Recorder Riddle?

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The discussion revolves around a riddle contest where participants post logic problems and riddles, taking turns to answer and create new ones. The initial riddle involves a murder disguised as a suicide, which participants quickly solve by noting that the tape recorder could not have been rewound if the victim had indeed committed suicide. Various other riddles follow, including brain teasers about a man using stairs instead of an elevator, twins with confusing birth certificates, and a sequence puzzle. Participants engage in lively exchanges, sharing answers and explanations while also debating the format of the thread, with some suggesting that individual riddles should have separate threads for better organization. The conversation highlights the enjoyment of logic puzzles and the social interaction they foster, despite some concerns about the structure of the thread.
  • #31
Icebreaker said:
One of the scientists with a red symbol stepped forward and said red. There are at least 2 reds and 1 blue because if otherwise, one person would see 2 blues, and would not have raised the hand. Therefore if the scientist who stepped forward sees one blue, then he knows he has a red one.

Nope. If that was the case then the puzzle would be too simple and they would have figured it out quickly. Because of the reasons you just put there.
 
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  • #32
You're assuming all scientists are that fast and brilliant. Perhaps the scientist that is confused by seeing 2 red ones and has a blue one on his forehead is simply faster than the other two, who are still contemplating the situation. After all, if every one of them sees 2 reds, how long should one deem "enough" to wait?
 
  • #33
colder, colder...

Rahmuss, this is a great riddle. I like it because it is both logical and psychological. IT really is a good test of intelligence.
 
  • #34
The other "possibility" is that they are all confused by the fact that they each see 2 reds, and therefore stayed in silence for a "long" time. But this is all subjective, as even in the other case there would have been a pause before any scientist replied.
 
  • #35
I'm not incredibly intelligent and it only took me a few seconds to realize that there were at least two red spots. But I didn't know if there were two or three spots. There is no logical way to know this. Assuming that all the scientists told the truth then they would quickly realize that nobody knew if there were 2 red spots or three. That would mean that nobody saw a blue dot. Thus all the dots must be red. It would take a while to guess that the other scientists had already come up with the easy logical answer. The smartest one would be the first to examine the psychology of the other scientists.
 
  • #36
I've been gone for too long...:rolleyes: :rolleyes:
 
  • #37
As has already been concluded from the other posts, there are only two possibilities: 2 red marks and 1 blue mark, or three red marks. (Although it doesn't take a person that long to realize that) But, if there are 2 red marks and 1 blue mark, then each of the scientists other than the one with the blue mark could easily conclude that they have a red mark since all three raised their hands and if one has a blue mark then the other person knows that he must have a red mark since the other person with the red mark also raised his hand. And the scientist who did answer the question answered "red" since each of the "smart" scientists took a while to answer and the scientist who did answer the question figured that if there was 1 blue mark and 2 red marks, then the scientist with the other red mark could easily conclude that he has a red mark on his head due to the fact that one of the scientists has a blue mark. Thus, the scientist who answered the question just figured that all three must be "red" since it would be easy if there were 2 blue and 1 red. Sorry about no commas and really long sentences.
 
  • #38
I'll give the answer to Huck. He answsered it first and gave a good enough explanation. Balls is in your court Huck. :smile:
 
  • #39
You throw it out when you want to use it. You bring it in when you don't want to use it. What is it?
 
  • #40
You throw it out when you want to use it. You bring it in when you don't want to use it. What is it?

In white:
Is it maybe an anchor?
 
  • #41
Yup, your up.
 
  • #42
Here's a visual one:
Below is a picture of a square with sides of unit lenght. Inside it is a smaller square. Divide the shaded area into four areas of same shape and size.
 

Attachments

  • #43
Can you give a link to the picture? (it's not working)
 
  • #44
I do not have permission to view it. Why not?
 
  • #45
i don't think anyone can view it
 
  • #46
Is it this?

As for attachments, log out and you will be able to see. Weird, and hope PF fixes it someday.
 

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  • #47
thanks icebreaker loging out worked, and no the image u provided is not the same as the one we tryed to originally access
 
  • #48
No, I mean I think I found the solution. The one I attached is my solution.
 
  • #49
ICEBREAKER! *slaps icebreaker* other people were supposed to solve the riddle, not you!
 
  • #51
Sorry it took me this long to reply.

Good work, Icebreaker. Your turn.
 
  • #52
yomamma said:
ICEBREAKER! *slaps icebreaker* other people were supposed to solve the riddle, not you!

Well that was certainly odd.

Berislav said:
Good work, Icebreaker. Your turn.

Find a counterexample to the Riemann hypothesis.

Just kidding. Here's an easy one:

The length of the perimeter of a right triangle is 60 and the length of its altitude perpenticular to the hypotenuse is 12. Find the sides and show your work.

Good luck.
 
  • #53
Icebreaker said:
The length of the perimeter of a right triangle is 60 and the length of its altitude perpenticular to the hypotenuse is 12. Find the sides and show your work.

Let a and b denote the lengths of the legs of the triangle, and let c denote the length of the hypotenuse.

60=a+b+c
a^2+b^2=c^2
ab/2=12c/2

Solving this system of equations, we get

a=15
b=20
c=25
 
  • #54
Yup. Your turn.
 
  • #55
Okay, moo of doom, your turn
 
  • #56
Yikes, I don't really have anything...

Here goes...
Find the next row in this sequence:

1
2, 1
3, 3, 2, 1
4, 4, 4, 3, 2, 1
5, 9, 10, 11, 12, 12, 12, 12, 12, 12, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
?
 
  • #57
6, 5, 9, 10, 11, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1


I'm really not sure, I took a huge guess
 
  • #58
Nope.

I'll give you a hint: it's more than twice as long as the last one. (sorry :P)
 
  • #59
Can you give a bigger hint?
 
  • #60
There are 62 numbers in the sequence, and the highest number in the sequence is 32, which is repeated 17 times.

There's another big hint I'm willing to give if it's absolutely necessary.
 

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