Mixing
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Fami-liar Situation
Clash Royale CLAN TAG#URR8PPP
up vote
2
down vote
favorite
Exactly one of Sam or Tom has family visiting. They make these statements:
Sam: "Tom has family visiting, but I don't."
Tom: "Sam is lying, or I am lying, or possibly we're both lying."
Which of the two men has family visiting?
Attribution: this puzzle is from The Mensa Puzzle Calendar, July 17, 2018. I solved it as intended but the solution doesn't sit right with me. I want to see what other solutions can be found.
logical-deduction liars
asked Sep 8 at 13:10
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
2
down vote
favorite
Exactly one of Sam or Tom has family visiting. They make these statements:
Sam: "Tom has family visiting, but I don't."
Tom: "Sam is lying, or I am lying, or possibly we're both lying."
Which of the two men has family visiting?
Attribution: this puzzle is from The Mensa Puzzle Calendar, July 17, 2018. I solved it as intended but the solution doesn't sit right with me. I want to see what other solutions can be found.
logical-deduction liars
asked Sep 8 at 13:10
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Yay! A user other than me finally has a big pie on their profile picture, from what I've seen :D
– user477343
Sep 8 at 13:22
Max, how do these solutions look in terms of adding clarity? Or were you thinking of a different way to show the answer altogether?
– El-Guest
Sep 8 at 13:30
@El-Guest the calendar gives a very thorough explanation of its answer (which you found). But I suspect that there are other answers.
– Max
Sep 8 at 13:35
2
Without more meta-information (such as: "one of Sam or Tom always tells the truth"), this isn't solvable or even a puzzle. Imagine that Sam only ever says this one sentence, and ditto for Tom. Either of them might have family visiting to listen to their nonsense for a while.
– Eric Tressler
Sep 8 at 16:43
Yeah, that was my thinking too. I was very disappointed that the calendar's explanation of it's answer assumed such meta-information.
– Max
Sep 9 at 6:27
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Exactly one of Sam or Tom has family visiting. They make these statements:
Sam: "Tom has family visiting, but I don't."
Tom: "Sam is lying, or I am lying, or possibly we're both lying."
Which of the two men has family visiting?
Attribution: this puzzle is from The Mensa Puzzle Calendar, July 17, 2018. I solved it as intended but the solution doesn't sit right with me. I want to see what other solutions can be found.
logical-deduction liars
asked Sep 8 at 13:10
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Exactly one of Sam or Tom has family visiting. They make these statements:
Sam: "Tom has family visiting, but I don't."
Tom: "Sam is lying, or I am lying, or possibly we're both lying."
Which of the two men has family visiting?
Attribution: this puzzle is from The Mensa Puzzle Calendar, July 17, 2018. I solved it as intended but the solution doesn't sit right with me. I want to see what other solutions can be found.
logical-deduction liars
asked Sep 8 at 13:10
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Sep 8 at 13:10
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Sep 8 at 13:10
Max
1113
asked Sep 8 at 13:10
Max
1113
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Yay! A user other than me finally has a big pie on their profile picture, from what I've seen :D
– user477343
Sep 8 at 13:22
Max, how do these solutions look in terms of adding clarity? Or were you thinking of a different way to show the answer altogether?
– El-Guest
Sep 8 at 13:30
@El-Guest the calendar gives a very thorough explanation of its answer (which you found). But I suspect that there are other answers.
– Max
Sep 8 at 13:35
2
Without more meta-information (such as: "one of Sam or Tom always tells the truth"), this isn't solvable or even a puzzle. Imagine that Sam only ever says this one sentence, and ditto for Tom. Either of them might have family visiting to listen to their nonsense for a while.
– Eric Tressler
Sep 8 at 16:43
Yeah, that was my thinking too. I was very disappointed that the calendar's explanation of it's answer assumed such meta-information.
– Max
Sep 9 at 6:27
add a comment |Â
Yay! A user other than me finally has a big pie on their profile picture, from what I've seen :D
– user477343
Sep 8 at 13:22
Max, how do these solutions look in terms of adding clarity? Or were you thinking of a different way to show the answer altogether?
– El-Guest
Sep 8 at 13:30
@El-Guest the calendar gives a very thorough explanation of its answer (which you found). But I suspect that there are other answers.
– Max
Sep 8 at 13:35
2
Without more meta-information (such as: "one of Sam or Tom always tells the truth"), this isn't solvable or even a puzzle. Imagine that Sam only ever says this one sentence, and ditto for Tom. Either of them might have family visiting to listen to their nonsense for a while.
– Eric Tressler
Sep 8 at 16:43
Yeah, that was my thinking too. I was very disappointed that the calendar's explanation of it's answer assumed such meta-information.
– Max
Sep 9 at 6:27
Yay! A user other than me finally has a big pie on their profile picture, from what I've seen :D
– user477343
Sep 8 at 13:22
Yay! A user other than me finally has a big pie on their profile picture, from what I've seen :D
– user477343
Sep 8 at 13:22
Max, how do these solutions look in terms of adding clarity? Or were you thinking of a different way to show the answer altogether?
– El-Guest
Sep 8 at 13:30
Max, how do these solutions look in terms of adding clarity? Or were you thinking of a different way to show the answer altogether?
– El-Guest
Sep 8 at 13:30
@El-Guest the calendar gives a very thorough explanation of its answer (which you found). But I suspect that there are other answers.
– Max
Sep 8 at 13:35
@El-Guest the calendar gives a very thorough explanation of its answer (which you found). But I suspect that there are other answers.
– Max
Sep 8 at 13:35
2
2
Without more meta-information (such as: "one of Sam or Tom always tells the truth"), this isn't solvable or even a puzzle. Imagine that Sam only ever says this one sentence, and ditto for Tom. Either of them might have family visiting to listen to their nonsense for a while.
– Eric Tressler
Sep 8 at 16:43
Without more meta-information (such as: "one of Sam or Tom always tells the truth"), this isn't solvable or even a puzzle. Imagine that Sam only ever says this one sentence, and ditto for Tom. Either of them might have family visiting to listen to their nonsense for a while.
– Eric Tressler
Sep 8 at 16:43
Yeah, that was my thinking too. I was very disappointed that the calendar's explanation of it's answer assumed such meta-information.
– Max
Sep 9 at 6:27
Yeah, that was my thinking too. I was very disappointed that the calendar's explanation of it's answer assumed such meta-information.
– Max
Sep 9 at 6:27
add a comment |Â
3 Answers
3
active
oldest
votes
up vote
3
down vote
If Tom is lying, that makes his statement true (a contradiction), so Tom must be telling the truth. This means Sam must be lying. Since exactly one of the men has family over, it must be Sam since otherwise Sam would be telling the truth.
answered Sep 8 at 13:20
jafe
5,1651366
1
El-Guest answered before you, but he completely rewrote it after your answer, so you get my upvote.
– Max
Sep 8 at 13:34
add a comment |Â
up vote
1
down vote
Update because I’m a dummy and it’s too early for my thinking brain:
I think that it is
Sam who has family over.
Reasoning:
Tom’s statement is true (he’s a truth teller) if either he is lying or if Sam is lying. Tom’s statement is false (he’s a liar) if both he and Sam tell the truth. The second scenario leads to a contradiction, because he needs to tell the truth in order to be a liar. Tom’s statement must therefore be true; and so Sam must be lying. It is therefore Sam who has family over.
answered Sep 8 at 13:15
El-Guest
9,6582051
damn it was a bit too slow :D
– Kevin L
Sep 8 at 13:27
add a comment |Â
up vote
0
down vote
This is not the Mensa-approved answer, but
The question never specifies that Sam and Tom give logically consistent information such as only telling complete truths or lies. Both of them could be spouting gibberish that has nothing to do with which one has family visiting. So the answer is that it is impossible to know which has family visiting.
answered Sep 9 at 6:26
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
If Tom is lying, that makes his statement true (a contradiction), so Tom must be telling the truth. This means Sam must be lying. Since exactly one of the men has family over, it must be Sam since otherwise Sam would be telling the truth.
answered Sep 8 at 13:20
jafe
5,1651366
1
El-Guest answered before you, but he completely rewrote it after your answer, so you get my upvote.
– Max
Sep 8 at 13:34
add a comment |Â
up vote
3
down vote
If Tom is lying, that makes his statement true (a contradiction), so Tom must be telling the truth. This means Sam must be lying. Since exactly one of the men has family over, it must be Sam since otherwise Sam would be telling the truth.
answered Sep 8 at 13:20
jafe
5,1651366
1
El-Guest answered before you, but he completely rewrote it after your answer, so you get my upvote.
– Max
Sep 8 at 13:34
add a comment |Â
up vote
3
down vote
up vote
3
down vote
If Tom is lying, that makes his statement true (a contradiction), so Tom must be telling the truth. This means Sam must be lying. Since exactly one of the men has family over, it must be Sam since otherwise Sam would be telling the truth.
answered Sep 8 at 13:20
jafe
5,1651366
If Tom is lying, that makes his statement true (a contradiction), so Tom must be telling the truth. This means Sam must be lying. Since exactly one of the men has family over, it must be Sam since otherwise Sam would be telling the truth.
answered Sep 8 at 13:20
jafe
5,1651366
edited Sep 8 at 13:33
answered Sep 8 at 13:20
jafe
5,1651366
answered Sep 8 at 13:20
jafe
5,1651366
answered Sep 8 at 13:20
jafe
5,1651366
5,1651366
1
El-Guest answered before you, but he completely rewrote it after your answer, so you get my upvote.
– Max
Sep 8 at 13:34
add a comment |Â
1
El-Guest answered before you, but he completely rewrote it after your answer, so you get my upvote.
– Max
Sep 8 at 13:34
1
1
El-Guest answered before you, but he completely rewrote it after your answer, so you get my upvote.
– Max
Sep 8 at 13:34
El-Guest answered before you, but he completely rewrote it after your answer, so you get my upvote.
– Max
Sep 8 at 13:34
add a comment |Â
up vote
1
down vote
Update because I’m a dummy and it’s too early for my thinking brain:
I think that it is
Sam who has family over.
Reasoning:
Tom’s statement is true (he’s a truth teller) if either he is lying or if Sam is lying. Tom’s statement is false (he’s a liar) if both he and Sam tell the truth. The second scenario leads to a contradiction, because he needs to tell the truth in order to be a liar. Tom’s statement must therefore be true; and so Sam must be lying. It is therefore Sam who has family over.
answered Sep 8 at 13:15
El-Guest
9,6582051
damn it was a bit too slow :D
– Kevin L
Sep 8 at 13:27
add a comment |Â
up vote
1
down vote
Update because I’m a dummy and it’s too early for my thinking brain:
I think that it is
Sam who has family over.
Reasoning:
Tom’s statement is true (he’s a truth teller) if either he is lying or if Sam is lying. Tom’s statement is false (he’s a liar) if both he and Sam tell the truth. The second scenario leads to a contradiction, because he needs to tell the truth in order to be a liar. Tom’s statement must therefore be true; and so Sam must be lying. It is therefore Sam who has family over.
answered Sep 8 at 13:15
El-Guest
9,6582051
damn it was a bit too slow :D
– Kevin L
Sep 8 at 13:27
add a comment |Â
up vote
1
down vote
up vote
1
down vote
Update because I’m a dummy and it’s too early for my thinking brain:
I think that it is
Sam who has family over.
Reasoning:
Tom’s statement is true (he’s a truth teller) if either he is lying or if Sam is lying. Tom’s statement is false (he’s a liar) if both he and Sam tell the truth. The second scenario leads to a contradiction, because he needs to tell the truth in order to be a liar. Tom’s statement must therefore be true; and so Sam must be lying. It is therefore Sam who has family over.
answered Sep 8 at 13:15
El-Guest
9,6582051
Update because I’m a dummy and it’s too early for my thinking brain:
I think that it is
Sam who has family over.
Reasoning:
Tom’s statement is true (he’s a truth teller) if either he is lying or if Sam is lying. Tom’s statement is false (he’s a liar) if both he and Sam tell the truth. The second scenario leads to a contradiction, because he needs to tell the truth in order to be a liar. Tom’s statement must therefore be true; and so Sam must be lying. It is therefore Sam who has family over.
answered Sep 8 at 13:15
El-Guest
9,6582051
edited Sep 8 at 13:28
answered Sep 8 at 13:15
El-Guest
9,6582051
answered Sep 8 at 13:15
El-Guest
9,6582051
answered Sep 8 at 13:15
El-Guest
9,6582051
9,6582051
damn it was a bit too slow :D
– Kevin L
Sep 8 at 13:27
add a comment |Â
damn it was a bit too slow :D
– Kevin L
Sep 8 at 13:27
damn it was a bit too slow :D
– Kevin L
Sep 8 at 13:27
damn it was a bit too slow :D
– Kevin L
Sep 8 at 13:27
add a comment |Â
up vote
0
down vote
This is not the Mensa-approved answer, but
The question never specifies that Sam and Tom give logically consistent information such as only telling complete truths or lies. Both of them could be spouting gibberish that has nothing to do with which one has family visiting. So the answer is that it is impossible to know which has family visiting.
answered Sep 9 at 6:26
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
0
down vote
This is not the Mensa-approved answer, but
The question never specifies that Sam and Tom give logically consistent information such as only telling complete truths or lies. Both of them could be spouting gibberish that has nothing to do with which one has family visiting. So the answer is that it is impossible to know which has family visiting.
answered Sep 9 at 6:26
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
up vote
0
down vote
up vote
0
down vote
This is not the Mensa-approved answer, but
The question never specifies that Sam and Tom give logically consistent information such as only telling complete truths or lies. Both of them could be spouting gibberish that has nothing to do with which one has family visiting. So the answer is that it is impossible to know which has family visiting.
answered Sep 9 at 6:26
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
This is not the Mensa-approved answer, but
The question never specifies that Sam and Tom give logically consistent information such as only telling complete truths or lies. Both of them could be spouting gibberish that has nothing to do with which one has family visiting. So the answer is that it is impossible to know which has family visiting.
answered Sep 9 at 6:26
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered Sep 9 at 6:26
Max
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
answered Sep 9 at 6:26
Max
1113
answered Sep 9 at 6:26
Max
1113
1113
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Max is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |Â
add a comment |Â
Max is a new contributor. Be nice, and check out our Code of Conduct.
Max is a new contributor. Be nice, and check out our Code of Conduct.
Max is a new contributor. Be nice, and check out our Code of Conduct.
Max is a new contributor. Be nice, and check out our Code of Conduct.
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Yay! A user other than me finally has a big pie on their profile picture, from what I've seen :D
– user477343
Sep 8 at 13:22
Max, how do these solutions look in terms of adding clarity? Or were you thinking of a different way to show the answer altogether?
– El-Guest
Sep 8 at 13:30
@El-Guest the calendar gives a very thorough explanation of its answer (which you found). But I suspect that there are other answers.
– Max
Sep 8 at 13:35
2
Without more meta-information (such as: "one of Sam or Tom always tells the truth"), this isn't solvable or even a puzzle. Imagine that Sam only ever says this one sentence, and ditto for Tom. Either of them might have family visiting to listen to their nonsense for a while.
– Eric Tressler
Sep 8 at 16:43
Yeah, that was my thinking too. I was very disappointed that the calendar's explanation of it's answer assumed such meta-information.
– Max
Sep 9 at 6:27