Originally Posted by
PharoahsWin
You are correct, Alan, this is a trick question. I want to explain why it's a trick question. It's something I think everyone is missing the point on. The question asks, "If you roll the dice, and at least one is a 2, what are the odds that BOTH dice rolled a 2?".
That's the wording of the original question, and it's worded pretty different than normal speech. Normally, you would ask the question, "If you roll the dice and at least one of the the die is a 2, what are the odds the OTHER die also rolled a 2?" You wouldn't ask about both dice, after explaining that one is already a 2, you would just ask about the OTHER die.
This is why it's a trick question. In the original question, the answer is 1/11, the odds of BOTH dice rolling a 2 is 1 in 11. And, that's what the question asks. It's not asking the odds of the other die rolling a 2, it's only asking the odds for BOTH dice rolling 2's.
In the second question, the one you would ask in normal speech, the chances of the OTHER die also rolling a 2 is 1/6. The odds of 1 particular die rolling a 2 is 1 in 6. And that's what the 2nd question asks. It doesn't ask the odds for BOTH dice rolling 2's, only the "other" die.
This is why the question is a trick question. It asks the question in a different way than you would normally speak, and by doing this it gives a different answer than would normally be given.
I think a lot of these math guys don't understand why it's a trick question, most would probably, incorrectly, give the same 1/11 answer to both wordings of the question. It just so happens, in this case they are correct, the question asks the odds of BOTH dice rolling a 2, that's 1/11. If the question was asked about the "other" die, you would be right with 1/6, and I'm guessing most of the math guys would give the wrong answer of 1/11. But, this is why it's a trick question.
If you do the experiment itself, you'll see that BOTH dice will roll 2's 1 in 11 times. And, the "other" die will have a 1 in 6 chance of rolling a 2, just like in your video. So, depending on whether you say BOTH dice, or if you say the OTHER die, you'll get 2 different answers.
The original question asks for BOTH dice, it does that on purpose, to get the 1/11 answer, because if it asked about the "other" die, it would get a totally different answer of 1/6 (and this would trick a lot of people who think it's 1/11). Hope this helps explain why this is such a tricky question for you.