Can You Send a Secret Code With 1 Letter?

Logic Level 1

An evil scientist has locked you in his lair and hands you a single button that will send the letter 'A' back to the secret agency you work for. He tells you the button will only work once, and once you press it, it will continue sending the letter 'A' until you press again to stop. The only thing you can tell is how many A's have been sent before you hit stop.

You tell him that if you send the agency a message saying "help me", they will storm the lair and rescue you, and you have planned for such a situation with the agency beforehand.

He walks out laughing, scoffing that such a feat is impossible. Is the evil scientist right? If not, how can you do it!

It is possible and I can explain! The scientist is right, it's impossible!

23 solutions

Vittorio Grandi
Jan 26, 2016

At every character of the message "helpme" corresponds a natural number in the alphabetical order, e.g. e->5. I indicate the ordinal number of a character with the symbol [character]. Therefore I send as many 'A' as the number 2^[h]•3 [e]•5 [l]•7 [p]▪11 [m]•13 [e]. The message can be correctly decoded due to the unique factorization theorem.

The question clearly stated that the button would only work once, therefore, you shouldn't be able to activate the button again after you've pressed the button a second time to stop sending the letter "A", also you do not know the frequency of which the letter "A" is sent, so you can't say that you would know how many times it has sent "A" before you need to stop the signal for your letter. That is why I don't believe that the solution would be sending every letter with an index, but since it is stated that you and the secret agency has planned for this in the past, you probably already have a plan such as, leaving the button to transmit "A" for 30 seconds as a, help me, call. So yes it is possible. But just trying to get my point across on the indexing letters with numbers solution.

Meaning Less - 5 years, 4 months ago

Psssssh, well there goes my plan.

Josh Edwards - 5 years, 2 months ago

Aren't the ordinal numbers for h, l, and p 8, 12, and 16 respectively?

Nick Barna - 4 years, 9 months ago

Ah those are the prime number factors. I understand.

Nick Barna - 4 years, 9 months ago

I can't seem to find the option to add my solution from mobile, so I'll just comment here instead because it's a similar idea:

However, instead of using factors, each letter has a 2-digit numeric code assigned to it. e.g. A= 01, B= 02, etc. Something similar to this was used in The Martian. Anyways, "helpme" would be (8)(05)(12)(16)(13)(05), or 80 512 161 305 consecutive As.

Ellie Marilanna - 4 years, 9 months ago

Edit: this is of course based on the hope that the button both pumps out As very quickly and it is easy to control exactly how many you want! Perhaps the villain will not have been quite so merciful but I do think this is the most easily decoded method :p

Ellie Marilanna - 4 years, 9 months ago

Tran Hieu
Jan 30, 2016

The correct solution is not sending the sum of the index of character in "help me" but to convert "help me" which in base 26 to base 10 and send this much character A

It seems like the clue is given in the question "you have planned for such a situation with agency beforehand". So, I believe whatever reason we may give can be acceptable because we are assuming that we have already discussed about the situation. For example, maybe if i just never stop sending the letter A could mean that I am in danger and "help me" or sending the fixed amount of letter A could be a secret code to say help me. Either one can be accepted given that we have already discussed about it beforehand. Please feel free to express your opinions about this.

Nima Sherpa - 5 years, 4 months ago

Excactly. Any number of A's can be the preplaned distress signal.

Thomas Oppenlænder - 3 years, 5 months ago

This is what I thought.

Amogh Kamath - 5 years, 4 months ago

but the problem isn't about sending A's. it's about being able to distinguish a specific sequence of A's to write a specific message being 'help me'. other responses suggest that sending messages similar to SOS or hello, 505 or 01134, but neither of these comply with the problem requirements, 'help me'

Benjamin Ninnemann - 5 years, 4 months ago

@Benjamin Ninnemann – What if my language only consists of the message 'help me' and that is denoted by non-stop a's?

Amogh Kamath - 5 years, 4 months ago

So you mean A=1 B=2 C=3 etc

So add up the sum of HELPME and sent that number of As?

I think that would be the the best solution, it is a predetermined code for rescue.

Richard Morgan - 5 years, 4 months ago

@Benjamin Ninnemann The question says you can tell how many As have been sent before you hit stop

Rucha Dalwadi - 4 years, 11 months ago

yeah the alphabets gets counted

Rahul thachil - 4 years, 5 months ago

The evil guy says the button will only work once though, so once the a's start sending they'll never stop

Benjamin Ninnemann - 5 years, 4 months ago

Yes. But the agency will know I'm in trouble if it sees the a's coming,

Amogh Kamath - 5 years, 4 months ago

the agency can't plan for the man to send a's because this isn't according to plan.... in another words the man can't know that an evil scientist will give him 1 button that produce a's without stop..

Omar Abdallah - 5 years, 4 months ago

this only could work if you knew the rate that the A's were being sent. there's no display or output. 1 second could send 5 or 200 A's and you would have no idea of knowing

Benjamin Ninnemann - 5 years, 4 months ago

Nayan Jain
Jan 31, 2016

there can be many possible solutions. one can be sending the sos, which can be achieved by sending 505 number of "A" as 505 resembles the SOS. another solution can be sending "hEllO". this can be done by sending 01134 which resembles hello when turned upside down.

surely it'd only be possible to send "hell" because the 0 at the start wouldn't appear? or do you mean for it to be backwards as well?

Lewis Conroy - 5 years, 4 months ago

The question says the message must say "help me," not sos or hello

Nick Barna - 4 years, 9 months ago

Agreed, and the only character available is "A"

Gavin Ouellette - 4 years, 6 months ago

Michael Nguyen
Jan 30, 2016

Simply: It is possible because you have pre-planned with The Agency for such a situation.

Scenario: Since all you have is a triggering device with no display so you cannot observe the speed at which the characters appear, the duration of the transmission will be the trigger regardless of what the transmission is. i.e. if the transmission lasts for exactly 23 seconds, I am in need of immediate rescue.

That would not be sending the agency a message stating "help me," which the question states you must do. Even if you get the agency to rescue you without saying "help me," the question isn't about being rescued, it is about whether or not the scientist is right. The scientist would still be right that it is an impossible feat to send "help me" if you just sent 23 seconds of A.

Nick Barna - 4 years, 9 months ago

Abhishek Sanjay
Aug 25, 2016

OK guys consider this .. i will send 3,006,134 times A ... as u can call it three million six thousand one hundred thirty four,..... i.e. 3 million and 6134 ...i.e. 3M 6134 .... which when inverted ... looks like ... hEl9 WE ....... since they are in intelligence agency .. they can understand 9 as P and W as M ... obviously

This is the only comment I have read that would really work.

Nick Barna - 4 years, 9 months ago

You can send 911 As, which definitely means emergency....!!!

Ramya M - 2 years, 3 months ago

Charlie Gillions
Jul 9, 2016

Keep sending A's and eventually the secret agency will track them both down.

Will Johnson
Jan 31, 2016

It's a button to use if you get caught and your cover is blown so if you press it and the agency starts receiving "A"s then it would be obvious that you are in danger and need help

Mohaimen Radi
Jan 28, 2016

Every letter has an index, A is 1,B is 2. In that case: H = 8, E = 5, L = 12, P = 16, M= 13, So the message "helpme" can be written as: 8,5,12,16,13,5 Or those many A's in our case

You can't stop and start the A's so how would they identify the different letters. It would just be a constant stream of A's till you stopped the button?

Sarah Mckenna - 4 years, 10 months ago

I get what you're saying, but the evil scientist said that the button would only work once. So what do you do?

Paul Sampson - 4 years, 4 months ago

Half-god Dragon
May 3, 2018

I had a fair idea of sending the number of letters based on in order they come and let the agency decipher it.

Ashkar Mohammed
Feb 1, 2016

It's simple. Just send a few A ; eg: AAA...
It's some sort of scream & the agency will know that I need help immediately

Kitty Hauser
Apr 2, 2021

There could be a code that is A = HELP ME or AA = Storm the lair.

J Serena
Jan 31, 2018

Many things are unknown, or undefined. So I guess at minimum, I went there to spy, go back to my agency and give some feedback. So I just stablished with them that WHATEVER message I send to them, it means I'm in danger and they shall storm the lair and rescue me. Otherwise I would just go back and safely give my report.

Thomas Grable
Jun 26, 2017

The solution is simple: AAAAAAAA. "Eight-A" sounds phonetically like "aidez," which is french for "help."

Utsav Garg
Jun 2, 2017

We will have assigned each letter to a unique prime number, in order: A as 2, B as 3, C as 5, D as 7 and so on. H will be 19, E will be 11, L will be 37, P will be 53, M will be 41, and E will again be 11. Their product is 184,841,899. Upon the transmission of these many As, the agency will factorize it and discover the letters, which they can easily unscramble to "help me".

Rahul Thachil
Dec 27, 2016

The number of times you click the button the alphabets too gets counted initially with the A's

Joel Kang
Aug 19, 2016

It is 2016, and anything is possible. Therefore, it is possible and i can explain.

Rik Bhattacharja
Jul 9, 2016

A simpler solution would be to use SOS in morse (· · · – – – · · ·). If A=. and AAA=_, then the message would be A A A AAA AAA AAA A A A.

You can only press the button twice, once for start sending, and once for stop sending. After that the button won't work.

Kryon Krenoteve - 4 years, 11 months ago

Palaash Barot
Jul 9, 2016

i think that when you have planned for such a situation with the agency you need not fix a number of A's.....the secret agency might come to know soon when they get the message.....

P.S.: Is That True???

Marcelo Almeida
Jul 8, 2016

60 times.

A-60 that would be understood, as ASSIST, by the Agency.

Jayadeep Cp
Jan 31, 2016

You can use the single letter A to create a coded message in Morse Code. And I'm sure the agency will be able to decode the message in seconds as decoding Mores code is not a big deal in cryptography. But I'm surprised why the evil scientist failed to realise this possibility.

But you can only press the button once, so morse code is impossible

Christopher Unrau - 5 years, 4 months ago

Achille 'Gilles'
Jan 31, 2016

Simply send three A, AAA.

First it could be confused by “American Automobile Association” but already that could be a hint that you are in need of assistance.

But 3 is already know by multiple authorities as an indication of “Help Needed”. As an example if you are lost in forest or in vast area, 3 campfires disposed in triangle is a well known signal for any aircraft pilot seeing it that somebody need help.

https://www.hunter-ed.com/arizona/studyGuide/Signaling-for-Help/20100401_700065488

Hfgds Fdd
Jan 31, 2016

Assume you cannot predetermine with the agency beforehand that 'A' simply equals "help me". In essence, the only information you can transmit is the length of the string of A's. One solution is to predetermine that space in between letters=0, a=1, b=2, c =3... then you can send 80501201601305 A's

I can't see that could be the solution, at a rate one A being sent every second it would take 2.5 million years to send the message.

Richard Morgan - 5 years, 4 months ago

I'm the OP... Plus if you you look at my reply below at my more efficient answer it would only require 26^6 A's which is 308915776 and it wouldn't take so long for a computer write 308915776's A's

hfgds fdd - 5 years, 4 months ago

There is a more efficient solution which requires predetermining a base 26 number system using letters thereby eliminating the need for spaces in between letters. Then any string can be sent since the possible permutations of any string of length k (or 6 in this case) is 26^k and the length of A's would correspond to the particular permutation of "help me".

hfgds fdd - 5 years, 4 months ago

Paulo Roberto de Souza
Jan 25, 2016

It is possible to use the button for sending a message in morse code. Example: A A A AAA AAA AAA A A A

Sorry if it wasn't clear but no spaces are allowed, you can only press the button once and it keeps sending 'A's until it turns off

hfgds fdd - 5 years, 4 months ago

It was hard to figure out exactly what the rules where.. I mean you could simply pre plan for a single A to mean help me

Mike Durkin - 5 years, 4 months ago

if you can only press the button once, how could you stop the signal if it requires to pressed again to be turned off?

Jesus Frankenstein - 5 years, 4 months ago

Can You Send a Secret Code With 1 Letter?

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