Is this math-based riddle too hard

[dascarletm]

Here is what the players will find on an encrypted hard drive.

They are looking for a password, which is a number, and it is supposedly on this storage device. However the data that is encrypted is a riddle to find the answer. Anyway here it is.

9*3=23
E*X=92
10-5=7
E+1=10
X/2=5

X*5=Answer

If the players do something I'll five them this hint

Spoiler: Hint

Show

The answer is fifty, but not 50

[DavidSh]

It looks pretty straightforward to me. The answer is

Spoiler: the answer

Show

the answer to the ultimate question, of life, the universe, and everything, at least in terms of digits

Spoiler: details

Show

calculations are in base 6*2

.

[dascarletm]

It looks pretty straightforward to me. The answer is

Spoiler: the answer

Show

the answer to the ultimate question, of life, the universe, and everything, at least in terms of digits

Spoiler: details

Show

calculations are in base 6*2

.

Yes, did you find that it was too easy?

and

What in particular made it too easy if it was?

[Anonymouswizard]

Yeah, the trick is that it all seems to that...

Spoiler

Show

It all seems to be base 12, which isn't a base I'm used to working in (I tend to use 8 or 16 when deviating from 10, because it converts to binary easily).

So instead of 9+9+9=27, you have 9+9=16, 14+9=13
E*X I'm not sure of at this point in the calculations.
10-5=7 is the easiest way to work out that it's base 12.
E+1=10, working back we can find out that this means E equals 11₁₀
From here we can in theory work out X, but I'm not confident dividing 92₁₆ by 11₁₀.
However, X/5=5 means that X must equal 10₁₀.

Using this we look at X*5=?, and we substitute in X=10₁₀.

Therefore the answer is 50₁₀ in base 12. Now this is where I fall down a bit, but by what I think is the way to convert between bases by hand, we have:
50/12=4 remainder 2.
Take the first number as the 'tens', second as the 'units'. Therefore, the answer is 42₁₂

That is, I think, the easiest way to do it by hand, it requires entirely on spotting 10-5=7 and realising the implication. For a harder riddle how about something along the lines of:

Spoiler

Show

When 10-5=7
6T+4U=28
2T+10U=24
XT+YU=?

The maths is harder, and it's still not in decimal, but it's still not unreasonable to work out. The real trick here is working out that T is the 'tens' and U is the 'Units'.

Disclaimer: please check with your group before excepting riddles from nameless mages. The Anonymouswizard will not be hold liable for any sessions that grind to a halt through application of his ideas.

[DavidSh]

It depends on who the audience is. If the players are math students, I think it is too easy. If they are, for example, history students, then it should be all right.

It may just be that my first few steps when seeing equations like 9*3=23 are

Spoiler: steps

Show

1: try another base than base ten.
2: try calculations modulo some number
3: try to redefine the symbols '*' and '=' in some way

[Socksy]

Spoiler: Answer

Show

Fifty, or 42.

Spoiler: Explanation

Show

I only used the first four equations.
9*3 = 23 established that it could not be any lower than base ten. As 9*3 is 27 in base ten, 9*3 = 23 must be base twelve. (27 = 2(x^1) + 3(x^0)).
10 - 5 = 7 confirmed this.
Now we know E = eleven, from E+1 = 10.

Using the second equation, eleven * X = 92 in base twelve.
So, eleven * X = 9(12^1) + 2(12^0) in base ten.
eleven * X = 110
X = ten

So X*5 is fifty, which is written as 42 as the question is in base twelve.

EDIT: @DavidSh I tried to redefine * at first, but I'm a maths student, so there's that.
I'd remove the X/2 = 5 bit. Too easy.

[NRSASD]

As an archaeologist, I have to admit that one made me stumble. But once I realized we aren't operating in base 10, it's simple enough. Just be aware that non-math majors may not make the same realization. I think I've only ever been introduced to non-base-10 systems once for a day in my entire educational career.

[JNAProductions]

Yeah, I'm a math person (or was, all throughout high school and my first semester of college) and I never got introduced to new bases. Make sure there are math majors.

[goto124]

But once I realized we aren't operating in base 10, it's simple enough. Just be aware that non-math majors may not make the same realization.

I... think this is beyond the reach of a lot of people, just due to this

And I thought it was plain algebra!

[nedz]

I found it to be easy from the first line:
9*3=23 tells you the trick.

But I have a maths degree so that might not be a useful observation.

Know your players - is the usual trick with these.

[kraftcheese]

Here is what the players will find on an encrypted hard drive.

They are looking for a password, which is a number, and it is supposedly on this storage device. However the data that is encrypted is a riddle to find the answer. Anyway here it is.

9*3=23
E*X=92
10-5=7
E+1=10
X/2=5

X*5=Answer

If the players do something I'll five them this hint

Spoiler: Hint

Show

The answer is fifty, but not 50

I guess it depends on who the players are; I have no idea why the answer is what it is (are you adding two on the end of every answer? And if so why? Because X should be 10 and E is 9 if that's what's happening, the only problem being Answer which???? I don't understand; its either 50 or 52 but why the extra 2????? What is it?) but I've only done basic highschool math, regular algebra etc.

If you're using a math rule or function theyre aware of they should be fine but yeah, if they don't have any experience with it (I.e. theyre a math pleb like me) you might wanna revise it.

[NRSASD]

Quick question: How do you represent eleven in a base 12 number system?

[Telok]

Traditionally you start using letters. In hex its a=10, b=11, etc.

[Milo v3]

My players would never figure it out since they didn't do anything beyond high-school mathematics.

[Beleriphon]

Quick question: How do you represent eleven in a base 12 number system?

Other symbols. Like in hexadecimal where you go 0-F where A to F represent the units ten through sixteen. The reason this puzzle works is because none of the numbers are ten or eleven, which if represented by letters rather than numerals gives away the trick. Doing this is in hexadecimal for example would be a give away since most people at least passingly familiar with computers should be able to recognize what's going on.

Like they say there are 10 kinds people in the world. Those who understand binary and those who don't.

Spoiler

Show

9*3=23 (total value is twenty-seven units, but in base 12 we have two units of twelve and three extra)
E*X=92 (nine groups of twelve, and two more)
10-5=7 ( in base twelve this is one group of twelve less five units = seven units)
E+1=10 (since we determined this is Base 12, the numerals 1 0 are a single unit of twelves and nothing else, so we have a total of E equals eleven units)
X/2=5 (as above anything divided in two parts equaling five units must be ten units)

X*5=Answer (42, or rather four groups of twelve and two extra)

[Quertus]

Here is what the players will find on an encrypted hard drive.

They are looking for a password, which is a number, and it is supposedly on this storage device. However the data that is encrypted is a riddle to find the answer. Anyway here it is.

9*3=23
E*X=92
10-5=7
E+1=10
X/2=5

X*5=Answer

If the players do something I'll five them this hint

Spoiler: Hint

Show

The answer is fifty, but not 50

So, I a) was a computer science major, math minor; b) I love puzzles; c) I'm something of a math genius (perfect 800 on math SATs, published my own math theory while in high school, etc).

I didn't find the puzzle hard, but that doesn't say much. 10-5=7, confirmed by 9*3=23, was the fun part. X/2=5, X*5=Answer was nice to trick people who would jump to the wrong answer. And many smart people I know would likely never be able to solve this puzzle. And certainly not have fun solving this.

So, know your players. How familiar are they with alternate bases? How much do they enjoy this type of puzzle?

I did, however, find it... odd. Why would anyone put their password on an unencrypted storage device, and encrypt it as a puzzle? Does the system you are playing have hacking skills?

I love puzzles In RPGs, but this just feels out of place to me.

[Feddlefew]

There's some precedent for these kinds of puzzles. The Myst series (and a few other adventure games) also had a few puzzles using non base 10 number systems. For instance, doing math in base 25 (Riven) and base 8, 60, and 2 (RAMA) were pretty standard back in the day. Usually you had to lean an alternative numbering system, too.

That being said, these games expected you to take your time and sleep on it if you couldn't figure it out. So, like others have said, it really depends on your players.

[Laserlight]

It depends on who the audience is. If the players are math students, I think it is too easy. If they are, for example, history students, then it should be all right.

I was a history and English major, back a few decades ago, and I got Base 12 within a few seconds from 9x3=23 and 10-5=7.

[georgie_leech]

Other symbols. Like in hexadecimal where you go 0-F where A to F represent the units ten through sixteen. The reason this puzzle works is because none of the numbers are ten or eleven, which if represented by letters rather than numerals gives away the trick. Doing this is in hexadecimal for example would be a give away since most people at least passingly familiar with computers should be able to recognize what's going on.

Like they say there are 10 kinds people in the world. Those who understand binary and those who don't.

Spoiler

Show

9*3=23 (total value is twenty-seven units, but in base 12 we have two units of twelve and three extra)
E*X=92 (nine groups of twelve, and two more)
10-5=7 ( in base twelve this is one group of twelve less five units = seven units)
E+1=10 (since we determined this is Base 12, the numerals 1 0 are a single unit of twelves and nothing else, so we have a total of E equals eleven units)
X/2=5 (as above anything divided in two parts equaling five units must be ten units)

X*5=Answer (42, or rather four groups of twelve and two extra)

I've always been fond of 'there are 10 kinds of people in the world: those who understand binary, those who don't, and those who aren't expecting a joke in base 3.'

[Anonymouswizard]

I've always been fond of 'there are 10 kinds of people in the world: those who understand binary, those who don't, and those who aren't expecting a joke in base 3.'

I've always heard it as 'and those who mistake it for trinary.'

Although my favourite has always been 'there are three types of people in the world, those who can count and those who can't.'

[AvatarVecna]

It was pretty easy for me to figure out...but then, I'm a person who annoyed enough people to prefer avoiding an entire sub-forum because at the time I was refusing to count in anything other than dozenal/dodecimal in a game based around counting. 9*3=23 showed me everything I needed to know for this, and I just skipped right to the end.

[Lord Torath]

I'd say it should be fine. Be ready with a couple of other clues that it is Base 12, though, or make it so solving the riddle is a bonus, not a necessity for moving the plot forward.

[dascarletm]

Quick question: How do you represent eleven in a base 12 number system?

I use E to represent eleven, and X to represent ten.

So, know your players. How familiar are they with alternate bases? How much do they enjoy this type of puzzle?

I did, however, find it... odd. Why would anyone put their password on an unencrypted storage device, and encrypt it as a puzzle? Does the system you are playing have hacking skills?

I love puzzles In RPGs, but this just feels out of place to me.

Well, the system is a cyberpunk game that I've been working on myself for some time, and I'm going to have my gaming group try it out within the next few months. The villain is going to be the type that likes to play with the investigators (the players). He may also be obsessed with the number twelve (yet tbd). So, if they go with 50, they will still advance the plot, but in a less fortunate way. If they go with 42 they will advance it in a positive way.

I'd say it should be fine. Be ready with a couple of other clues that it is Base 12, though, or make it so solving the riddle is a bonus, not a necessity for moving the plot forward.

I expected it to be too easy for most of the people coming in here (since the title would draw math lovers). However, my players are smart people, but I'm not sure if they've done alternate base systems before. I do think I can actually cut-down on the clues due to everyone's feedback. They really like riddles, and they like being stumped by a challenge. Hopefully they won't think to look at different base systems right away.

EDIT: also the riddle isn't needed to advance the plot, it just allows them to narrow down 50 buildings they can search.

[ComaVision]

As someone who stopped taking math classes in university as soon as I could, I didn't get this even after reading the solution. I get it now but I had read most of the posts in this thread before it clicked. There's no way I'd get this on the spot.

[dascarletm]

As someone who stopped taking math classes in university as soon as I could, I didn't get this even after reading the solution. I get it now but I had read most of the posts in this thread before it clicked. There's no way I'd get this on the spot.

If it proves too hard for my players perhaps I'll drop a hint about it being in base 12. Not sure what that hint is yet... any suggestions?

[Raimun]

Without reading, yes. Yes, it is.

"I'm not here fo no math. Now, let me calculate my attack and damage modifiers and we're good to go."

[ComaVision]

If it proves too hard for my players perhaps I'll drop a hint about it being in base 12. Not sure what that hint is yet... any suggestions?

I'm not even sure if telling them flat out that it's base 12 would mean anything. It wasn't until people starting talking about binary and such that I realized. If I didn't have any familiarity with that then I'd be googling 'base 12' right now.

[Pex]

Spoiler

Show

I got an answer of 42.

42? I see some shenanigans here.

It's base 12 math.

X = 10 in base 10 so X * 5 = 50 in base 10 which is 42 in base 12.

[N810]

Give them a hint that it's in feet and inches.

[BWR]

We can't answer this for you, you know your players better than we.
In both my groups this would probably be solved fairly quickly. No pure mathematicians here but at least one programmer in each, and a physics doctorate in one (not sure if the biology doctor would get it or not, but it wouldn't surprise me), and a History major who is quite bright and likes math in the other. As an English major it took me a bit of fooling around before I realized that I had to be thinking in different bases. Longer than would be fun to waste time on in a game, but more people might make things go faster.
However both groups also have people who have literally been reduced to tears at the sight of anything more complicated than simple arithmetic.

This is also the perfect example of a situation where character stats are more important than player abilities. It would for instance be most unfair to have a PC be e.g. a professor of math but have them be unable to solve this simply because the player sucks at anything containing numbers, then have the illiterate, innumerate mentally deficient brick solve it because that player knows this stuff.
Sure, you might argue that so long as one player solves it, in game it is the most appropriate PC who comes up with it, but what happens if you have appropriate PCs and the players cannot solve it?

What I do in these situations is I would give the puzzle to the players, let them try to solve it with their own brainpower and if that fails, let their characters roll for it.