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Old 10-06-2016, 01:34 PM
octopus octopus is offline
Join Date: Apr 2015
Posts: 6,129
Originally Posted by DrDeth View Post
Not if one die is given to be a six.

Ok, the question is badly worded, so let's look at it another way. One of the dice has to be a six, right?

So let us toss two dice, one is normal the other has 6's on all faces. What is then the chance of the other die rolling a 6?
If it's only asked when one is a 6? Then the answer is 1/6. Independent each have 1/6 chance.

But lets do the red die green die list of possibilities.

1 6
2 6
3 6
4 6
5 6
6 6

6 1
6 2
6 3
6 4
6 5
6 6

There are 12 different combinations in which a 6 can be given. Six that are green and six that are red 6s. That's why you can count the 6 6 twice because you are given a different die. You are given either the red or the green so it's two events. Ok you have twelve possible and equally likely events. Only two still have a 6 left over. 2/12 gives 1/6 which is what should be expected treating dice as individual events and only doing this in the trials you have at least one 6 rolled.