Incorrect sum of geometric series

User

**Name**
Nick C

**Username**
@NickCicc

**Contact**
nicholascicchino@gmail.com

Debug

**Browser**
Mobile Firefox 153.0

**Engine**
Gecko 153.0

**OS**
Android 17

**Device**
mobile

**CPU**
\-

**Page**
/lessons/256-bit-security/

**Subject**
Incorrect sum of geometric series

**Message**
There is an error in the explanation of how to calculate the number of expected rolls to roll a specific number on a d6. If you do what the explanation says and plug 5/6 into the sum of the geometric series as written, you get 36, not 6. This is because the sum should instead be 1/6 / (1 - x)^2.