Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

? asked in Science & MathematicsMathematics · 8 years ago

A probability math question?

If you could figure out any of the parts to this i would greatly appreciate it! (The three parts are a, b, and c, but i understand if you don't know them all). If you know how to do any of them at all please answer and maybe show your work too if it's not too much to ask? I want to be able to follow along and see how you solve it, thank you!

Attachment image

1 Answer

Relevance
  • ?
    Lv 4
    8 years ago
    Favorite Answer

    I can't see this too clearly but I think all of them but 6 say 1/9, right? And 6 is 1/2? I'll proceed under those assumptions. Now for part 1, we know that the probability has to add up to 1 (I'm sure you'll get something if you roll), so we say that 1/2+1/9+1/9+1/9+1/9+k=1. Now, that's just 4/9+1/2=9/18+8/18=17/18, so k=1/18.

    For part 2 we just have to find the probability in each scenario. If she picked the fair dice, the probability should be 1/3, whereas if she picked the biased dice it should be 11/18. Assuming she has an equal probability of picking either dice, we should just take the average and we find that 6/18+11/18=17/18, divide by 2 and our probability should be 17/36.

    TECHNICALLY, the fact that she rolled a point doesn't ACTUALLY tell us anything about which dice she picked. The probability of her having picked a dice is still 50-50. However, I get what the problem is asking. It's saying, the probability of her getting a point with the fair dice is 1/3. However, the probability of having rolled the biased dice and getting a point is 11/18. Now, the likeliness of her having chosen a die is proportional to the likelihood of her getting a point with the die (since we know she did get that point), so the ratio is 11/18 to 1/3. That is, the answer should be 11/18, I believe.

Still have questions? Get your answers by asking now.