Jump to content


Welcome to BrainDen.com - Brain Teasers Forum

Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account.
As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends.

Of course, you can also enjoy our collection of amazing optical illusions and cool math games.

If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top.
If you have a website, we would appreciate a little link to BrainDen.

Thanks and enjoy the Den :-)
Guest Message by DevFuse
 

Photo
- - - - -


  • Please log in to reply
3 replies to this topic

#1 jamie bickers

jamie bickers

    Newbie

  • Members
  • Pip
  • 6 posts

Posted 08 January 2008 - 09:34 PM

If you throw a dice once the cance of getting six is 1/6
If you throw a dice twice the cance of getting six is 2/6
If you throw a dice three times the cance of getting six is 3/6
If you throw a dice four times the cance of getting six is 4/6
If you throw a dice five times the cance of getting six is 5/6

Does this mean that if you throw a dice 6 times you are garantied 6?
Of course it doesn't but how come theareticly the chance is 100% when practicly it isn't.
  • 0

#2 bonanova

bonanova

    bonanova

  • Moderator
  • PipPipPipPip
  • 5569 posts
  • Gender:Male
  • Location:New York

Posted 08 January 2008 - 10:06 PM

If you throw a dice once the cance of getting six is 1/6
If you throw a dice twice the cance of getting six is 2/6
If you throw a dice three times the cance of getting six is 3/6
If you throw a dice four times the cance of getting six is 4/6
If you throw a dice five times the cance of getting six is 5/6

Does this mean that if you throw a dice 6 times you are garantied 6?
Of course it doesn't but how come theareticly the chance is 100% when practicly it isn't.

Spoiler for Only your first statement is true.

  • 0
The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#3 spoxjox

spoxjox

    Junior Member

  • Members
  • PipPip
  • 97 posts

Posted 08 January 2008 - 10:09 PM

If you throw a dice once the cance of getting six is 1/6
If you throw a dice twice the cance of getting six is 2/6
If you throw a dice three times the cance of getting six is 3/6
If you throw a dice four times the cance of getting six is 4/6
If you throw a dice five times the cance of getting six is 5/6

Does this mean that if you throw a dice 6 times you are garantied 6?
Of course it doesn't but how come theareticly the chance is 100% when practicly it isn't.

Your odds aren't quite right.

If you throw a die (btw, singular is 'die', plural is 'dice') you have a one in six chance of getting a specified number, e.g. six. That means you have five chances in six of not getting a six.

In two dice rolls, your chances of not getting a six are 5/6 for the first roll and 5/6 for the second roll, giving you total odds of (5/6) * (5/6), or 25/36, of not getting a six. Thus, your odds for getting at least one six are one (100% odds) minus the odds of not getting at least one six: 1 - 25/36, or 11/36. Note that this is slightly smaller than 2/6 (= 12/36), as you had said above.

In six dice rolls, your odds of not getting a six are therefore (5/6)^6, or 15625/46656, which is just a bit greater than 1/3 odds. Therefore, your odds of rolling at least one six are one minus this amount, which as a percent is 66.5%.
  • 0

#4 caecae

caecae

    Newbie

  • Members
  • Pip
  • 1 posts

Posted 08 January 2008 - 10:12 PM

Ok. well i may not be right but here it goes any way. well i read it a few times and there is a problem because even if you role a die 6 time the prob is going to remain at 1/6 chance for each role but the as you roll the die more times your chance of gettin a six will increase. so i did the math because it was really bugging me and if you roll the dice 6 times it is actually a 40% chance or a 2.4/6 chance of getting a six. i got this from my stat class.
  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users