Dice game problem

Jamarlie

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Mar 11, 2018
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Dice game problem within the game "Kingdom Come: Deliverance"

First of all, hello guys!
So I was recently playing Kingdom Come: Deliverance and there's a cool little dice game within the game.
Now I wanted to device a few strategies and calculate a few probabilities for that game but unfortunately after tinkering with the numbers over a night for a bit I came to a complete stop and can't advance any further.
The game itself works as follows for those of you who haven't played it:
Each player has 6 dice. On each roll they have to throw either a 1, a 5, or a triplet, quadruplet, quintuplet or 6x the same number to get another roll.
After each roll the player has to remove at least one dice if he gets a second roll. Let's say I roll 5 4 2 3 2 6 then I get a new roll since I got a 5, I have to take the 5 away and reroll with the remaining 5 dice. I would also get a reroll if I got 4 2 2 2 3 3 and I would remove the 3 dice I rolled a 2 with, giving me a reroll with the remaining two dice.
There are point values associated with all of that but that isn't really relevant for the problem that I encountered.

So first off I started to calculate what the probability of rolling either a 5 or a 1 is with 1 (33%), 2 (56%), 3 (70,38%), 4 (80,24%), 5 (86,83%) and 6 (91,22%) dice. So far so good (hopefully). I simply calculated the outcome of having a "no hit" on each of these dice numbers and multiplied the probabilities for it, meaning (2/3)^n with n being the number of dice. So with 6 dice we get a probability of 1 - (2/3)^6 for not getting a hit, aka ~91,22%.

Now what we have is the probability of rolling either a 1 or a 5 on our throw but here is where my trouble began. Since you also get a reroll if you get a triplet, quadruplet and so on, the probabilities of these cases have to also be added to the existing 91,22% probability to get a full accurate picture on the probability of getting a reroll.
And this is where my math kinda failed hard.
I tried simplifying the problem looking at 3 dice first and looking at their probability of rolling either 3 x 2, 3 x 3, 3 x 4 or 3 x 6.
With three dice I only have 4 possibilities of rolling a triplet of 2s, 3s, 4s and 6s:

222
333
444
666

That gave me 4/216 (the total number of possibilities for 3 dice to land, aka 6^3, which is roughly 1,85%. Or, simpler put, for the first throw you have a 2/3 chance of hitting a 2, 3, 4 or 6, for the two consecutive throws it's a 1/6 chance to hit the same number again. So 2/3 x (1/6)^2 = ~0,0185 which is the probability.
Now when I tried expanding this model to 4 dice I kinda got stuck.
I tried writing out all the different possibilities for triples, of which there are 4x4=16 variants:

X X X -
X X - X
X - X X
- X X X

The x represents a number 2, 3, 4 or 6. So for each line there's 4 combinations, equaling up to 16 possible solutions for the triplets.
However, now that there are 4 dice there are also 4 possibilities for quadruplets, which would be 4x2, 4x3, 4x4 or 4x6.
So there are 20 possibilities that we get a reroll via triples or quadruplets on 4 dice, right?

But if I try to calculate the number of possibilities for triplets using my math from earlier, I get to a sticking point.
So we could still use the formula 2/3 x (1/6)^2 in theory but we would have to expand it with a 4th dice, right? So the 4th dice cannot be the same as the first three and it cannot be 1 or 5 since we already calculated that. So if our triplet would be 3 2s we would have to get either a 3, a 4 or a 6, aka 3/6, aka 1/2.
So if I expand this formula then I get this:
2/3 x (1/6)^2 x 1/2= 0,00925...
And 0.00925 x 1296 (number of possible throws aka 6^4) = 12?
But that can't be the number of possible triplets for 4 dice as I've shown above?

So does anybody know how I could progress from that sticking point and maybe even move all the way up towards the probability of 6 dice giving you a reroll on your throw?
Where is my mistake in that calculation? Where am I taking a wrong turn? Is there a more simple way of calculating this, a more easy way that I can't see at the moment?

Cause I've been trying to solve this sticking point for a few hours now and I can't seem to progress any further.

If there are any questions regarding anything, feel free to ask me.

Cheers!
 
Last edited:
I hope it's okay to bump this since the thread was down dze to an edit of mine for 3 days or so, still haven't gotten a solution
 
First of all, hello guys!
I tried writing out all the different possibilities for triples, of which there are 4x4=16 variants:

X X X -
X X - X
X - X X
- X X X

The x represents a number 2, 3, 4 or 6. So for each line there's 4 combinations, equaling up to 16 possible solutions for the triplets.
However, now that there are 4 dice there are also 4 possibilities for quadruplets, which would be 4x2, 4x3, 4x4 or 4x6.
So there are 20 possibilities that we get a reroll via triples or quadruplets on 4 dice, right?

But if I try to calculate the number of possibilities for triplets using my math from earlier, I get to a sticking point.
So we could still use the formula 2/3 x (1/6)^2 in theory but we would have to expand it with a 4th dice, right? So the 4th dice cannot be the same as the first three and it cannot be 1 or 5 since we already calculated that. So if our triplet would be 3 2s we would have to get either a 3, a 4 or a 6, aka 3/6, aka 1/2.
So if I expand this formula then I get this:
2/3 x (1/6)^2 x 1/2= 0,00925...
And 0.00925 x 1296 (number of possible throws aka 6^4) = 12?
But that can't be the number of possible triplets for 4 dice as I've shown above?

So does anybody know how I could progress from that sticking point and maybe even move all the way up towards the probability of 6 dice giving you a reroll on your throw?
Where is my mistake in that calculation? Where am I taking a wrong turn? Is there a more simple way of calculating this, a more easy way that I can't see at the moment?

Cause I've been trying to solve this sticking point for a few hours now and I can't seem to progress any further.

If there are any questions regarding anything, feel free to ask me.

Cheers!


Hi Jamarlie! Welcome to the forum.

The equation (2/3)*(1/6)^2 * (some factor) doesn't expand directly from the three dice case to the four dice case, because it doesn't take into account the ordering of the dice, which matters now that there is an odd man out.

From the permutations you drew using your X symbols above, we know that there are four possible orderings in the case of a triplet. Multiply that by the number of possible triplet values, which is four (2,3,4, or 6). You end up with 16 triplets having an unknown odd man out. Multiply that by the number of ways of choosing a value for the odd man out, which is 3 (because three possible values exist for the odd man out. E.g. if you triplet has 2s in it, then the possible odd man out values are 3,4, and 6). You end up with 16*3 = 48 triplets.

Now if we try to compute it the way you did, we have

6^4 * (2/3) * (1/6)^2 * (1/2) = 12

But multiplying the probabilities in this order assumes that:

- first you pick a value out of the set (2,3,4,6) to be first die
- then you pick values for the second and third dice that match this first value
- then you pick one of the remaining allowed values for the fourth die.

I.e. this case only covers the permutation XXX_

Once you've done this selection, you have to multiply the number of ways of doing so by the number of ways of reordering the dice. There are 4 dice, so there are 4! ways of ordering them. However, three of them are exactly the same, so internally reordering those three doesn't change the outcome. So you have to divide by the number of ways of reordering these three, which is 3!

12 * (4!)/(3!) = 12*4 = 48 triplets.
 
Hi Jamarlie! Welcome to the forum.

The equation (2/3)*(1/6)^2 * (some factor) doesn't expand directly from the three dice case to the four dice case, because it doesn't take into account the ordering of the dice, which matters now that there is an odd man out.

From the permutations you drew using your X symbols above, we know that there are four possible orderings in the case of a triplet. Multiply that by the number of possible triplet values, which is four (2,3,4, or 6). You end up with 16 triplets having an unknown odd man out. Multiply that by the number of ways of choosing a value for the odd man out, which is 3 (because three possible values exist for the odd man out. E.g. if you triplet has 2s in it, then the possible odd man out values are 3,4, and 6). You end up with 16*3 = 48 triplets.

Now if we try to compute it the way you did, we have

6^4 * (2/3) * (1/6)^2 * (1/2) = 12

But multiplying the probabilities in this order assumes that:

- first you pick a value out of the set (2,3,4,6) to be first die
- then you pick values for the second and third dice that match this first value
- then you pick one of the remaining allowed values for the fourth die.

I.e. this case only covers the permutation XXX_

Once you've done this selection, you have to multiply the number of ways of doing so by the number of ways of reordering the dice. There are 4 dice, so there are 4! ways of ordering them. However, three of them are exactly the same, so internally reordering those three doesn't change the outcome. So you have to divide by the number of ways of reordering these three, which is 3!

12 * (4!)/(3!) = 12*4 = 48 triplets.

Ahhhh so that was where I went wrong! I didn't specifically thought the order was important. Thank you for your help, I will get back to that problem in a few days and try to resolve it!
 
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