Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

mathdummy4

  • 2 years ago

PLEASE HELP a dice is rolled 8 times. find the probability. p(getting at least 7 even numbers) a. 1/256 b. 9/256 c. 1/32 d. 1/16

  • This Question is Closed
  1. mathdummy4
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    any ideas?

  2. ganeshie8
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    total number of permutations when a dice is rolled 8 times = 6^8

  3. WLB250219
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    \[3/48\]= x

  4. ganeshie8
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    even numbers : 2, 4, 6 so, out of 8 times u perform experiment, 7 times - u have 3 choices : 3^7 one time you have 6 choices : 6 total permutations in favor = 3^7 * 6

  5. mathdummy4
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    how did you get 3/48??

  6. mathmate
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    At least 7 even is the same as at most 1 odd. 0 odd = 1/256 1 odd = 8/256 Total = 9/256

  7. ganeshie8
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    p(getting at least 7 even numbers) = \(\frac{3^7*6}{6^8}\) = \(\frac{3^7}{6^7}\) = \(\frac{3^7}{3^7.2^7}\) =\(\frac{1}{2^7}\) =\(\frac{1}{256}\)

  8. WLB250219
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    there are 3 even numbers on a dice and 3 odd and you dividethe 3 even by 8 times and that will give you the answer

  9. WLB250219
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    6times 8 is 48 and divide by 3 and you will get 16 so the answer is 1/16

  10. mathdummy4
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    okay...so what if you were looking for 8 odd numbers? wouldn't it be the same process?

  11. WLB250219
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

  12. mathdummy4
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    well i got the same answer..1/16...is that right?

  13. WLB250219
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

  14. mathmate
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Binomial distribution: P(n,i)=(n,i)p^i q^(n-i) (n,i)=n!/(i!(n-i)!) Here, p=q=1/2 (8,0)=1 (8,1)=8 (8,2)=8*9/2=36, ... So any number of even or odd can be calculated.

  15. eliassaab
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You have to have 7 throws even and the 8th one can be either. \[ \frac 1{2^7} 8=\frac 1 {16} \]

  16. eliassaab
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You multiply by 8 to count where the even or odd throw is.

  17. WLB250219
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1344014586415:dw|yes

  18. mathdummy4
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    thanks:)

  19. WLB250219
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    your welcome

  20. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.