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Let see if you all can break this one:

Bob and jack are standing facing each other and wearing cowboy hats. they are told that there are 11 feathers divided into 2 colors: black and white. Bob has 6 of those feathers attached to his hat and Jack has 5 attached to his hat. None of them can see the feathers attached to the other's hat. they are also told that the number of the black feathers is either higher or lower by 1 that the number of the white feathers. each one of them was asked "do you know how many of the feathers attached to your hat are black and how many are white?" the answers were as follows:

Bob: I don't know

Jack: I don't know

Bod: I don't know

Jack: I don't know

Bod: I don't know

Jack: I don't know

Bod: I Know!

How many feathers behind Bob's back are black and how many are white?

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0 white and 0 black. Bob has feathers on his hat, not behind his back.

If Bob actually knows that, it's because Bod told him.

I'll have to rethink this....

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Well, I can't find the thread, but I'm 100% sure this has been posted before :dry:

Also, yeah, the feathers....

behind his back.

You could also say that since they can't see each others feathers that they must be standing back to back... so how many are on Jack's head? Just a thought

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Let see if you all can break this one:

Bob and jack are standing facing each other and wearing cowboy hats. they are told that there are 11 feathers divided into 2 colors: black and white. Bob has 6 of those feathers attached to his hat and Jack has 5 attached to his hat. None of them can see the feathers attached to the other's hat. they are also told that the number of the black feathers is either higher or lower by 1 that the number of the white feathers. each one of them was asked "do you know how many of the feathers attached to your hat are black and how many are white?" the answers were as follows:

Bob: I don't know

Jack: I don't know

Bod: I don't know

Jack: I don't know

Bod: I don't know

Jack: I don't know

Bod: I Know!

How many feathers behind Bob's back are black and how many are white?

It says they cannot see the feathers in the OTHER persons hat, but they are asked how many feather are in THEIR OWN hat. So either they cannot see any hats and nobody would ever know, or they CAN see their own hat in which case nobody would ever not know. I think rewording is in order.

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I agree with wafflechip and if they are faceing each other why can't they see the others hat and the feathers in it?(unless they have their eyes shut, which wasn't stated in the OP) Are you sure you have stated the puzzle correctly? :huh:

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Let see if you all can break this one:

Bob and jack are standing facing each other and wearing cowboy hats. they are told that there are 11 feathers divided into 2 colors: black and white. Bob has 6 of those feathers attached to his hat and Jack has 5 attached to his hat. None of them can see the feathers attached to the other's hat. they are also told that the number of the black feathers is either higher or lower by 1 that the number of the white feathers. each one of them was asked "do you know how many of the feathers attached to your hat are black and how many are white?" the answers were as follows:

Bob: I don't know

Jack: I don't know

Bod: I don't know

Jack: I don't know

Bod: I don't know

Jack: I don't know

Bod: I Know!

How many feathers behind Bob's back are black and how many are white?

Do you mean:

Neither of them can see the feathers attached his own hat.?

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Do you mean:

Neither of them can see the feathers attached his own hat.?

It sure makes the whole discussion more sensible. So,

Answer: B has 3w,3b

Proof:

For abbreviation, the feather state is always stated in the order Black, White. So "32" means "3W 2B".

1)Here's what Bob knows: If he has

60: he would see J05

51: J14 or j05

42: j23 or j14

33: j32 or j23

24: j41 or j32

15: j50 or j41

06: j50

Since anything Jack can wear corresponds to two possible Bob holdings, Bob doesn't know anything.

2) If Jack has 05, he would see B60 or B51

14: B51 or B42

23: B42 or B33

32: B33 or B24

41: B24 or B15

50: B15 or B06

Thus, if Jack sees B60, J has 05; if Jack sees B06 J has 50. Since Jack doesn't know, J sees B51, 42, 33, 24, 15

3) Bob has: Bob sees

51: J14 J05

42: J23 J14

33: J32 j23

24: j41 j32

15: j50 j41

So, if Bob sees J14 or J41, he knows what he's wearing. But Bob doesn't know. Therefore B sees J14, 23, 32, 41

4) Jack has: Jack sees

14: B51 B42

23: B42 B33

32: B33 B24

41: B24 B15

So, if Jack sees B51 or B15, Jack knows what he's wearing. But Jack doesn't know, so J sees B42, 33, 24

5) Bob has: Bob sees

42: J23 j14

33: j32 j23

24: j41 j32

If bob sees j14 or j41, Bob knows wht he's wearing, but Bob doesn't, so B sees j23 or j32

6) Jack has: Jack sees

23: B42 or B33

32: B33 or B24

If jack sees B42 or B24, Jack knows what he's wearing, but Jack doesn't, so B33

7) Bob knows immediately that he has 33

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Woops, fixing numerous errors:

Answer: B has 3 black, 3 white

Proof:

For abbreviation, the feather state is always stated in the order Black, White. So "32" means "3 Black, 2 White".

1)Here's what Bob knows: If he has

60: he would see J05

51: J14 or j05

42: j23 or j14

33: j32 or j23

24: j41 or j32

15: j50 or j41

06: j50

Since anything Jack can wear corresponds to two possible Bob holdings, Bob doesn't know anything.

2) If Jack has 05, he would see B60 or B51

14: B51 or B42

23: B42 or B33

32: B33 or B24

41: B24 or B15

50: B15 or B06

Thus, if Jack sees B60, J has 05; if Jack sees B06 J has 50. Since Jack doesn't know, J sees B51, 42, 33, 24, 15

3) Bob has: Bob sees

51: J14 J05

42: J23 J14

33: J32 j23

24: j41 j32

15: j50 j41

So, if Bob sees J05 or J50, he knows what he's wearing. But Bob doesn't know. Therefore B sees J14, 23, 32, 41

4) Jack has: Jack sees

14: B51 B42

23: B42 B33

32: B33 B24

41: B24 B15

So, if Jack sees B51 or B15, Jack knows what he's wearing. But Jack doesn't know, so J sees B42, 33, 24

5) Bob has: Bob sees

42: J23 j14

33: j32 j23

24: j41 j32

If bob sees j14 or j41, Bob knows what he's wearing, but Bob doesn't, so B sees j23 or j32

6) Jack has: Jack sees

23: B42 or B33

32: B33 or B24

If jack sees B42 or B24, Jack knows what he's wearing, but Jack doesn't, so B33

7) Bob knows immediately that he has 33

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