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@my maths puzzle:

I don't know if anyone's still working on it :D , but here's a hint:

All possible solutions to the solvable settings have a few things in common. If you can solve one or more of them, you can use a similar method to solve the rest. :)

My friends at the other forum manage to solve it already. One of them summed up the nature of the solutions quite nicely.

Exact quote:

assumptions

ใน operator สามอันที่ต้องเลือกมี / แน่นอน (ไม่งั้นคงคิดออกไปนานแล้ว)

operator ที่ทำอันสุดท้ายต้องเป็น *,/ (เพื่อให้เศษส่วนที่เกิดขึ้นระหว่างทางกลับเป็นจำนวนเต็ม)

อีก operator นึงเป็น +,- (สังเกตจากคำตอบของโจทย์ข้อที่คิดได้แล้ว)

Hmm.... what? What do you mean, you can't read it? :D

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1,7,8,9 -> 36

8/(1-(7/9)) = 36

3,3,8,8 -> 24

8/(3-(8/3)) = 24

1,4,5,6 -> 24

6/((5/4)-1) = 24

I'll edit as I come up with more...

1,2,8,9 -> 76

1,4,7,8 -> 58

1,4,8,9 -> 74

1,6,7,8 -> 24

2,4,6,8 -> 51

3,4,7,8 -> 10

3,6,6,9 -> 22

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Here is an easy one for now:

There are 3 boxes each with 2 marbles in them.

In one box there are 2 white marbles, in another there are 2 black marbles and in another there is one white and one black marble.

The boxes all have labels on them indicating what marbles they contain.

Somebody comes and rearranges the labels so that no box has the correct label anymore.

You are able to select one box and take one marble out.

How will you determine which label belongs to which box.

No, the boxes are not see-through etc, no trick just a simple riddle.

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Perhaps this one will tickle your fancy more?

Also a simple riddle, this time more math orientated:

An ordinary deck of playing cards contains 52 cards divided into 4 suits, diamonds, hearts, clubs, spades.

Each suit contains 13 cards of the following denominations from smallest value to greatest:

2, 3, 4, 5, 6, 7, 8, 9, 10, J (jack), Q (queen), K (king), and A (ace).

The game of poker is played with an ordinary deck of playing cards in which a player will have a five-card hand.

There is a certain five-card holding called two pairs.

It contains 2 cards of one denomination, 2 cards of a second denomination, and a fifth card of a third denomination.

How many five-card poker hands contain two pairs?

If a five-card hand is dealt at random from an ordinary deck of playing cards, what is the probability that the hand contains two pairs?

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I hereby ban myself from answering Rendril's (first) riddle. :)

Is that just to give others a chance? Maybe I should too... though I thought that was what spoiler tags were for. I wouldn't have jumped in so quickly with

mosquito

before; it was mostly a guess - but I suppose that's why they always tell you to go with your first answer. :)

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Lol

What gets wetter the more it dries?

I see two possible answers:

1) A towel, by drying some it will get wetter.

or

2) A block of ice, by drying (getting hotter) it will melt and hence get wetter.

Sorry if I don't use the spoiler bar correctly, I'm new to this.

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@Rendril:

Sorry, it's not that I don't like your riddle. It's just that once a riddle is solved, even with spoiler tags, people will stop bothering with it (or it has always been the case so far in this thread). Since that riddle was easy for me, that post was a way of showing off without spoiling the answer. :)

@Two-pair poker hands:

Not sure if I got it right, but here goes anyway:

Let C(A,N) = A!/(N!(A-N)!)

Number of five-card poker hands containing "two pairs"

= (number of ways to possible 1st and 2nd denominations) * (number of possible suits of the two pairs) * (number of possible third denomination) * (number of possible suits of the third denomination)

= C(13,2) * C(4,2)^2 * (11) * (4)

= 78 * 36 * 11 * 4

= 30888 (I just added *4 after getting the first wrong 'answer', and I forgot to recalculate)

= 123552

The number of possible 5-card hands dealt from a standard deck of 52 cards

= C(52,5)

So the probability that one such 5-card hand contains "two pairs"

= ( C(13,2) * C(4,2)^2 * (11) * (4) ) / C(52,5)

= 30888/2598960

= 99/8330

~ 0.011884753901560624249699879951981 (From previous mistake)

= 123552/2598960

= 198/4165

~ 0.047539015606242496998799519807923

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@Sacosphilz

I know what you meant, I didn't think you didn't like it, I just thought I'd give you another

one to keep you busy.

As for your solution, it is the correct method by the wrong answer.

78 * 36 * 11 * 4 does not equal 30888.

Otherwise, with the correct follow through you got it.

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The first two solutions you just posted are among the few that most people managed to solve last. Interesting. :)

Good luck with the other 7, they should be easier. :)

That's about par for me... I'll think of the situation that no one else will, but have a tendency to completely miss the blatantly obvious. :)

The 3,3,8,8 combination I had been challenged with before though, so it was more remembering how I solved it the last time; the other just fit the pattern nicely.

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That's about par for me... I'll think of the situation that no one else will, but have a tendency to completely miss the blatantly obvious. :)

The 3,3,8,8 combination I had been challenged with before though, so it was more remembering how I solved it the last time; the other just fit the pattern nicely.

In my case, the one I had been challenged with before was the 1,4,5,6 combination (and I couldn't solve it by myself and had to resort to some programming :), and then I was inspired to come up with 3,3,8,8 on my own. I never knew it was going around somewhere else before. Great minds think alike, huh? :)

@Your current 3 solutions:

Two weeks ago, chewett sent me a PM asking for confirmation if 9 out of those 10 combinations can truly be solved, because he could only solve 6 of them at that time and had 4 remaining (1 fake). The three combinations you just solved, Trahern, were all in those remaining 4. :)

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@Your current 3 solutions:

Two weeks ago, chewett sent me a PM asking for confirmation if 9 out of those 10 combinations can truly be solved, because he could only solve 6 of them at that time and had 4 remaining (1 fake). The three combinations you just solved, Trahern, were all in those remaining 4. :)

Sooo... I just spent the last 10 min not realising there was a fake. I got 9 out of 10 of them... and ummm kept trying.

(1/2+9)*8 = 76

6/(5/4-1) = 24

(1/4+7)*8 = 58

(1/4+9)*8 = 74

1678->24 (trap)

8/(1-7/9) = 36

(2/4+8)*6 = 51

8/(3-8/3) = 24

(3-7/4)*8 = 10

(6/9+3)*6 = 22

Oh also on the crown puzzle:

There are 4 optimal solutions bellow's an example of another one.

First person answers white if they see two white, and black if they see two black.

Second person black if they see a black and a white (in that order) or white if they see a white and a black.

Third person answers black if they see a black and a white (in that order) and white if they see a white and a black.

Basically anything which has only one person answering when they're right and has all three people answering when they're wrong will give a 75% success rate.

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MB I think you made a mistake on the 'I have no Brother's or Sisters. But This Man's Father is my Father's Son.' puzzle.

If the speaker is the answer then one would be able to replace "this man's" with "my"...

"My Father is my Father's Son."

Which clearly doesn't work. It does work if "this man" refers to the son of the speaker.

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And here's another (some what famous one).

There are 100 pirates who have 100 gold pieces from a recent plunder. The pirates are ordered from the highest ranking to the lowest ranking. At any point the highest ranking pirate (who is alive) is the Captain. The Captain gets to decide how to divide up the plunder any way he/she likes. However if after the treasure is divided up more than 50% (including the captain and strictly more not greater than or equal to) decide to rebel then they will rise up and kill the captain making the next in line re-divide the plunder.

Now these of course happen to be a rare breed of perfect rational actor pirates and each know that the other pirates are similarly perfectly rational. They have the following motivations. First they don't want to be killed, second they want as much money as they can get (without getting killed), and third if it means they get the same amount of money they'd rather kill the captain just to see some blood.

Give the above how does the captain distribute the booty and why?

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@Eldrad:

On 9/10 math puzzle:

You left out one solution. :)

On 3 crowns riddle:

Trahern's answer made me think that there might be such possibilities, but I never fully thought them out. Good job on finding and defining the optimal alternatives. :)

On 100 pirates:

I've seen that one before, but I've completely forgotten the answer, so I'll be working on it.

By the way, does 50% mean 50% of the other pirates (excluding the captain), or is the captain included in the total too?

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