Friday, August 8, 2014

Roll 17 and 20 on d20

During one session in the D&D module I needed to roll 2 15+ on 2 d20's. One of the players yells out "roll a 17 and 20 Dog!" So I did.

 
 Here are the 2 d20's with a 17 and 20.
 
 
 
So, can some stat's person work out the odds of me rolling these 2 numbers.
 
1) We know a combination of 15,16,17,18,19,20 and 15,16,17,18,19,20 are going to be called because these are what I need to roll. So how many different combinations of these two sets of numbers are there?
 
2) The two dice being rolled are d20's with the numbers 1,2,3...18,19,20 and 1,2,3...18,19,20. and what are the odds of the two dice rolling a 17 and 20?
 


 
 


1 comment:

  1. I think I know. the chance of making the call that we did was one in 400. once in every 20 rolls are going to Rolla 17. then one time in 20 out of the times you roll 17 you roll a 20. 20 X 20=400.

    rolling 15+ is a 30% chance. 30 percent times 30 percent equals nine percent. not as amazing as the quarter of a percent but still...

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