# Ask one verbal question to figure out who is blind and who is mute among three persons

This is another "You can ask only one question" puzzle. This is an edited very restricted version

There may be multiple answers but I could come up with only one.

There are three persons in three seperate rooms. They have no idea about each other what-so-ever. They do not know that other persons are there in other rooms either.

Two have disabilities: One blind and the other is mute (can hear but unfortunately can't talk). They do not know each other. From their physical appearance you cannot know of their disabilities. The third one has no disability. There is no color blindness among the two either.

You need to ask one question verbally to all three going in the three rooms. Same exact question needs to be repeated in all three rooms in same exact way. YOU CANNOT MENTION ANY DISABILITY IN THE QUESTION.

They will answer only by raising their hands. Right hand for YES, Left hand for NO. If they cannot answer they are instructed to stay silent. They will be truthful.

After their answer you need to pin point who is blind and who is mute and the remaining.

State any assumption you have for your answer. The question needs to be objective so the three can only have those 3 answers. Question like "Do you think I am fat?" can be considered very subjective.

I do understand that there could be multiple answers but I hope the moderators don't consider this an open ended question.

• You mention the three people don't know each other. Does that also mean they don't know that there is exactly 1 mute, 1 blind and 1 abled? – P1storius Aug 29 '19 at 10:46
• That is right @MKBakker – DrD Aug 29 '19 at 10:53
• Nothing frustrates me more, than when a valid answer is given, but this is not intedend answer by the asker, the asker keep changing his question by making those already given answers invalid. Ususaly the answerer either have to leave now invalid answer up, or delete it altogether, and both options feel unfair and unsatisfying. – Andrew Savinykh Aug 31 '19 at 0:30
• I suspect even with its current reformulation, this question is probably still too broad; there's a couple answers already that seem to fit the bill, and I can think of at least one more that should also work. – Rubio Sep 1 '19 at 23:57
• That notwithstanding. your efforts to tighten up the question have left A LOT of answers no longer valid. Edits are "a balancing act between being fair to both the puzzle and its solvers by making the puzzle actually solvable as intended, and being fair to both the existing answers and their writers by not turning them into so much wasted effort.". I think you've broken that balance here. – Rubio Sep 1 '19 at 23:57

I think this could be an answer:

Can you pronounce this word? (pointing to some written word)

- The non-impaired: YES (right hand up)
- The mute: NO (left hand up)
- The blind: No answer (No hand up due to lack of information: What word?)

• The title seems to require a verbal (in the sense of spoken) question, and while the question is certainly delivered verbally, it wouldn't work without the non-verbal component. Replacing the gesture with rot13("vs V jrer gb fubj lbh n jbeq sebz n qvpgvbanel)" should fix this. – Bass Mar 6 '20 at 16:45

"What would you say, if I asked if you were blind, and you were allowed to respond verbally?"

so that:

Blind person raises hand for yes. Non-disabled person raises hand for no. Mute person would not be able to respond verbally, and raises no hands. You only said that it must have those three answers - not that it must be a standard yes/no question.

• @DEEM no... because it's not asking "what is true", it's asking "what would you tell me (ie, verbally) if I asked? – Ben Barden Aug 28 '19 at 16:17
• Easy to turn this into a standard yes/no question by replacing "what would you say" by "would you say yes". – Rand al'Thor Aug 29 '19 at 9:15
• @Randal'Thor Nope. That would change the answer of the mute person. – Ben Barden Aug 29 '19 at 13:00
• According to OP you cannot mention any disability. You should reword to avoid use of the word "blind." – Level River St Aug 30 '19 at 23:27
• @LevelRiverSt DEEM didn't like this answer and changed the question post-hoc, so that is their fault. This poster answered the question that was asked. – Greg Schmit Aug 31 '19 at 14:51

Is there a mute in the room?

Such that:

1. The blind and the abled person don't know if there is, so they will wait (and see)
2. The mute will raise their hand right away
3. The abled person now knows that there is a mute, and will respond to that by raising their hand. Which happens clearly after the mute did
4. The blind person, unable to see what is going on will keep their hands down

• They are in separate rooms – Michael Aug 30 '19 at 22:38
• @Michael Yes, the question was edited, basically into a new one. I will get back with a new answer – P1storius Aug 31 '19 at 7:09

Could you honestly say my eyes are blue? (or some other truthful visual fact about yourself)

That way:

The blind person can't know whether the fact is true or not, so will raise no hands. The mute person can't speak so would raise their left hand. The neither blind nor mute person would be able to know and speak truthfully so would raise their right hand.

And I would know who's who.

• >! I think the first sentence is false because they would have to raise their left hand. – Michael Aug 30 '19 at 22:56

Original Incorrect Answer: Before question was edited.
You could

Write on a piece of paper "Are you mute?" and show it to them.

The question does not state that asking be done verbally.

Result

The blind person won't raise any hand, the mute person will raise their right hand and the other person will raise their left hand

• I apologize @hexomino but I should have mentioned no writing. My bad – DrD Aug 28 '19 at 15:18
• @DEEM I'd assume there are no raising your own hand either? – Abbas Aug 28 '19 at 15:22
• That I did not say. Clever though. – DrD Aug 28 '19 at 15:24
• The new question assumes that they know things about each other... specifically that they know that there is only one mute character, and that they know that they all know that. – Ben Barden Aug 28 '19 at 16:21
• @DEEM How come hexomino is not entitled to write things but gustavovelascoh may point at a written word? A bit unfair, huh? – Arnaud Mortier Aug 29 '19 at 21:41

The question would be

Raise my hand, and then ask, If you are mute lie, am I raising my hand?

Explanation

Blind won't raise his hand. Mute will raise his left and the third will raise his right.

• "They will be truthful" – Ben Barden Aug 28 '19 at 15:34
• @BenBarden Hmm... that's a good point. Although it is possible to be truthful when asked to lie.... – Abbas Aug 28 '19 at 15:36
• Perhaps in the same vein - "Do not answer until I raise my hand: Are you mute?" – rm-vanda Aug 28 '19 at 19:07
• @rm-vanda That does make the question simpler and unambiguous. – Abbas Aug 29 '19 at 10:53
• Yeah, I realise that after commenting – not good form to edit the question and invalidate about a dozen answers. – Janus Bahs Jacquet Aug 31 '19 at 7:57

You say:

One of you is blind, another is mute and the other is normal. If I was to add either $$0$$ or $$1$$ to the number of people with disabilities you can see, would you have a number greater than $$1$$?

And then:

The blind person sees $$0$$, the mute can see $$1$$, the normal $$2$$.
The sum results in: $$0+0\lor1\le1,1+0\lor1\ge1,2+0\lor1\gt1$$
So 'No, Don't Know (the mute now has either $$1$$ or $$2$$), Yes' indicate 'Blind, Mute, Normal' respectively.

• @JMP sorry, I misunderstood your answer before. – hexomino Aug 28 '19 at 16:35

Here's a somewhat simpler answer that doesn't need props or nested questions:

"Does your disability prevent you from speaking?"

Mute: Signals Yes
Blind: Signals No
Able: Explicitly has no disability, thus cannot answer.

• You cannot mention any disability in the question – that presumably also goes for phrasings like “your disability”. – Janus Bahs Jacquet Aug 30 '19 at 22:57

You could simply ask "Is there a person to your left that you can talk to?"

Explanation

The Blind person will always stay still. They do not know if there is anyone to their left.
The Mute person will always answer "No". They cannot talk.
The Able person will always answer "Yes", Unless there is nobody on their left.
If two people answer "No Then that means the able person is on the far left (from their perspective) because that is the only position that they could say "no". So the other "No" therefor must be the mute.

You could ask (not really a question, but could probably be worded that way).

"When I raise my index finger, please raise the hand that corresponds to whether you are mute."

This means that

The blind person will not answer (cannot see visual cue), the mute should raise their right hand, and the other person should raise their left hand.

"What would you vocalize if I were to ask you 'Am I holding up three fingers'?", but actually only hold up two fingers for them to see.

This would mean that...

The blind man person would stay silent, since he cannot see and verify the number of fingers held up. The one with no disability should answer "No", since he can see they are wrong. The mute person should stay silent as well, since they cannot normally vocalize either "Yes" or "No".

• they can only raise their hands to answer – DrD Aug 28 '19 at 18:59
• I understand that. They are raising their left hand to say "No", because they would vocalize No. – APrough Aug 28 '19 at 19:07
• Editing due to the fact that you can't differentiate between those with disabilities. – APrough Aug 28 '19 at 19:14

Observation: Blindness is a perceptual, muteness an expressive disability. Therefore compose the question as a conjunction of two yes/no questions, one of which requires perception, the other the capability of articulatory expression to be answered. This question would elicit a 'YES' from the unimpeded respondent, a 'DO NOT KNOW' from the blind, and a 'NO' from the mute one.

Example:
'Do I have blond hair and can you give me a phone call later this week ?' [assuming that the interrogator has blond hair]

blind: Does nothing, as the answer would depend on the hair color.
mute: No
other: Yes

The only caveat is the indirect reference to the disability of muteness, though there is no explicit mention.

I would try

Without losing your disabilities, if you see someone you know, can you go and talk to him/her ?

That way

Obviously no-disability says yes and mute says no
Blind should say nothing since the "if" doesn't make sense to him

I find the cleanest solution is:

"Would you be able to tell me what this object is?" while pointing to an object. The blind person would give no answer, as they don't know if they would know what the object is or not, the mute would answer no, and the third would answer yes

That means that

The blind person would say yes, the mute person no and the third person doesn't have a disability so he stays silent.

Many of the answers seem to violate the question of not being able to mention any disability in the question, or ignore the fact that the three people don't know of each other and aren't in the same room.

The question says we can't mention any disability, so instead we have to ask a question that implies the opposite, that is, whether or not the person can do something, or is able.

"Giving the same answer that you would have given had you been required to speak it aloud instead of giving hand signals, can you identify the color of my shirt?"

Blind person: No (they can't see the shirt)
Mute person: No answer (they can't speak and would not be able to give an answer aloud, so cannot answer using a sign)
Sighted person: Yes (question stipulates no color blindness)

Updated to hopefully eliminate the irreal spotted by @JanusBahsJacquet

• Most of the answers were written before the rule about not mentioning the disability and the bit about the three rooms were edited into the question, which is presumably why they violate/ignore them. (Apart from that, in your answer I’d expect the mute to answer YES: since the if clause is an irreal – i.e., counterfactual – clause, the fact that the mute person cannot vocalise does not change what their answer would be here.) – Janus Bahs Jacquet Aug 30 '19 at 23:07
• @JanusBahsJacquet Ah good point... does that fix make it better? – Michael Aug 30 '19 at 23:31

Maybe not the perfect answer but I would...

Hold up a book and ask Could you read aloud from this book? 1. The mute would raise their hand for no, as they cannot speak. 2. The Blind person would not answer, as the book could be written in print, or it could be written in braille. 3. The able bodied person would raise their hand for yes.

Question (even better if not facing the people in the room while asking, but turn around to see potential answer): Can you see?

Mute will do nothing, able-bodied person will raise right hand, blind person will raise left.

• Why would the mute person not raise their right hand to signal "yes"? – Vaelus Aug 31 '19 at 8:53

Could you sing a song (even if it’s off pitch). Well, in all honesty I had forgotten about the third not disabled person. But perhaps a visual cue like an eye roll would help.

• Welcome to Puzzling.SE! Can you please clarify your answer a bit more? Happy puzzling :) – Zoir Oct 1 '19 at 5:23