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With the release of 8th edition, I see myself needing to make a lot of 9" charges (not 8", as you to set up more than 9" away). I also noticed that re-rolls let you re-roll one or both dice. I've not seen the math worked out on that problem so I worked it out:

Probability of a 9" charge, no re-rolls = 10/36 (27.7%).

If you can only re-roll both dice the odds go to 10/36 + 26/36 * 10/36 = 47.8%
The first part is the success of getting a 9" charge on the first roll. The second part is the probability of failing your first rolling combined with making it on your second.

Now, if you can choose to re-roll one or both of your dice, you have to figure out where the sweet spot is on re-rolling one vs. both. Simply put you should keep any dice that are 4 or greater (unless you rolled two 4s, then keep one). This is because the chance of getting a 5 or 6, if one die is a 4 (1/3) beets the probability of a success if you re-roll dice (10/36).

The math gets tedious but for instance if you rolled a 4 (1/6) that was part of an unsuccessful roll (1/6 * 2/3), you have a 1/3 chance of making the re-roll succeeding (1/6 * 2/3 * 1/3). If you do this for all available options, then you end up with a 52.5% chance of success. It surprised me that this is only about 5% better than only having the option of re-rolling both dice.


Edit: Clearly, I'm better at math than English.

gratz on doing mathhammer

I was bored a week ago and just worked out every result. My totals matched yours, so yay!

 Trickstick wrote:
I was bored a week ago and just worked out every result. My totals matched yours, so yay!

Wait! What if we're both wrong?

I just copied and used your homework....so mine matched yours too!!

Hope I still get a good grade...even if I don't understand it lol


Automatically Appended Next Post:

 cinnabar wrote:

 Trickstick wrote:
I was bored a week ago and just worked out every result. My totals matched yours, so yay!

Wait! What if we're both wrong?

oh no!!! there goes my test scores!!! I hate when cheating fails

But you need a ten inch charge.

Nope. Nine. You need to make it to within an inch with the new rules, not base to base.

 jeff white wrote:
But you need a ten inch charge.

No you don't. You only need to be within 1" of the enemy to make a successful charge. So a 9" charge is more than enough to get you within 1" of the enemy.