BIG Dice Roll!

[RayZorback]

What is the probability of rolling a 7 on a 120 sided dice? 1/120
What is the probability of rolling a 7 on a 120 sided dice out of 36 rolls? ____

How do you calculate this?

I'm not in school, I'm just curious because the numbers are in a game I play.
Thanks for the help!

EDIT: Please also explain the difference in "Expected Outcome" & "Probability". I think that is where I'm getting hung up.

 

[galactus]

The probability of NOT rolling a 7 in 36 rolls would be \(\displaystyle (\frac{119}{120})^{36}\approx{.74}\)

Therefore, the probability of rolling AT LEAST one seven would be \(\displaystyle 1-(\frac{119}{120})^{36}=.26\)

The probaility of rolling EXACTLY one 7 in 36 rolls would be \(\displaystyle 36(\frac{1}{120})(\frac{119}{120})^{35}\approx{.223}\)

Here is a curious one. What would be the probability of rolling all 7's out of 36 rolls. Intuitively, we know it would be astronomically low. \(\displaystyle (\frac{1}{120})^{36}=1.4108\times{10^{-75}}\)

 

[RayZorback]

YOU ARE GREAT! Thanks!

 

[galactus]

YOU ARE GREAT! Thanks!

I know, but I try not to let it go to my head.

 

[RayZorback]

YOU ARE GREAT! Thanks!

I know, but I try not to let it go to my head.

But what is the difference in the terms "expected outcome" & "probability" - mathematically speaking of course.