BrainDen.com - Brain Teasers

# bushindo

VIP

719

5

1. ## Stamps and foreheads

There are many cases on purpose. The reasoning should be straight forward with the proper tools and elimination procedure.
2. ## Stamps and foreheads

This is based on bonanova's puzzle Here's a game that goes as in the following * There is a host with 14 stamps, 7 red and 7 blue. There are five players- A, B, C, D, and E. * In the beginning, the host affixes two stamps to each of the 5 players' head. The remaining 4 stamps go into the host's pocket. Each player can see the stamps on the remaining 4 players, but can not see his own stamps nor the four in the host's pocket. * Starting from A to E (and then looping back to A and so on), the host asks if each player definitively knows his stamps distribution (RR, BB, or RB). If the pla
3. ## Truth, lies and pot luck

As stated in the OP any audience member who is not a truth-teller or a liar will randomly lie or tell the truth. If you like, s/he could make that decision by coin flip. Clarifications, please 1) Does each member of the audience know the type of all remaining audience member? 2) For the audience members that randomly tell the truth or lie, at any moment, do they know whether they will lie or tell the truth to the next question? That is, before hearing a particular question, have they already decided on lying or telling the truth?
4. ## Staying alive with an eight-sided die

Good solve, CaptainEd. Nice and compact solution =)
5. ## Staying alive with an eight-sided die

Here's an approach

My guess
7. ## First to Fifteen

Here's a winning strategy In this example, doesn't 2nd player win on his 3rd move having (2,7,6)? Shucks, back to the drawing board.

9. ## First to Fifteen

Here's a winning strategy

11. ## Closed form expression on steroids

This is based on a previous Find a closed form expression for function f(N) such that f( N ) = 0 for 1 <= N <= 11 f( N ) = 1 for 12 <= N <= 22 f( N ) = 2 for 23 <= N <= 33 f( N ) = 3 for 34 <= N <= 44 f( N ) = 4 for 45 <= N <= 55 ... No modulus or rounding operators are allowed.
12. ## All numbers showing

I agree with the note about median. I think the problem here is that the OP and post 14 (see blue-colored part in spoiler above) are conflating the median and the average (or mean) in the interpretation of the winning condition
13. ## Can you find a closed form equation for the sequence?

Here's one that doesn't use floor or mod
14. ## 1 = 2 revisited

This is great - beautiful, even.Except, the power tower unfortunately does not converge for both cases (for 2, but alas not for 4 as I remember.) I made a graph of the divergence point sometime back, I will look for it. When the records are written, however, this def gets Honorable Mention. Great proof as well. I have no beef with the power tower, but isn't the argument similar to this one
15. ## Yellow,Green,Red,Blue

If only a binary signaling scheme is allowed, CaptainEd has shown that only prisoner 1 needs to change his mind. Even in the stricter NS view, there are some latitude to define a quadnary signaling scheme due to an implied necessary condition
16. ## 1 = 2 revisited

Counter example to this proof =)

18. ## Yellow,Green,Red,Blue

Continuing with the community solve approach, can we clarify: Must all the persons in a particular row face the same direction? If prisoners in say the Yellow row can face in differing directions does that constitute [illegal] communication? Can the first two prisoners choose the time that they [legally] alter their position, at any time up to the last prisoner takes his place? During making raws...some of them can be..back to back (in any raw)...but by reaching the last prisoner,they all shoud be at the same direction But only the first two prisoners can move. This
19. ## Hitting 137

Here is the recursive code I used. The logic behind it is already described by Prime's excellent and insightful analysis.
20. ## Hitting 137

With some recursive code, I get
21. ## DOWRY

Okay, second time is the charm,
22. ## DOWRY

Forgot about some cases in computation of winning chance. Back to the drawing board.
23. ## DOWRY

Here's an approach,
24. ## Deal or No Deal

The problem is skillfully analyzed and solved by k-man and bonanova. Kudos, everyone. Yes, the Monty Hall reference was meant as a red herring, but apparently that false clue isn't enough around these parts.
25. ## Deal or No Deal

Here's a twist on the Monty Hall problem. Some of you might be familiar with a show called Deal or No Deal. For those you are not familiar, a simplified version of the show is as follows, * There is a host, a player, and 40 suitcases of money. * The host informs the player that there are 39 empty suitcases and 1 case with 1 million dollars. The suitcases are closed and the player has no idea how much each specific suitcase contains. At the beginning of the game, the player is requested to choose 1 suitcase at random. Let's call this the Chosen Suitcase * At the beginning of each turn, t
×

• #### Activity

• Riddles
×
• Create New...