Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

windsylph

Probability: Joe is a fool with probability 0.6, a thief with probability 0.7, and neither with probability 0.25. Determine the probability that he is a fool or a thief but not both.

  • one year ago
  • one year ago

  • This Question is Closed
  1. apple_pi
    Best Response
    You've already chosen the best response.
    Medals 0

    What is probability of Joe being not a thief. Similarly what is probability of not being a fool?

    • one year ago
  2. windsylph
    Best Response
    You've already chosen the best response.
    Medals 0

    My answer is 0.2, since the probability of Joe being a thief, a fool, or both a thief and a fool is 1-0.25 = 0.75, and 0.75 = P(Joe is thief) + P(Joe is fool) - P(Joe is thief and fool) = 0.6 + 0.7 - x. x = 0.55, and (0.6 + 0.7) - 0.55 = 0.2, which is the probability of Joe being a thief or a fool but not both. Please confirm?

    • one year ago
  3. windsylph
    Best Response
    You've already chosen the best response.
    Medals 0

    wait, I meant 0.75 - 0.55, not 0.6 + 0.7 - 0.55

    • one year ago
  4. windsylph
    Best Response
    You've already chosen the best response.
    Medals 0

    because 0.75 is already thief, fool, or both, and 0.55 is only both, so if i subtract 0.55 from 0.75, I get thief OR fool, right?

    • one year ago
  5. apple_pi
    Best Response
    You've already chosen the best response.
    Medals 0

    Ok first off, when we 'add' probabilities so like P(THIS and THAT) we multiply P(THIS) and P(THAT) The way I would do it is get P(fool but not thief) + P(thief but not fool)

    • one year ago
  6. windsylph
    Best Response
    You've already chosen the best response.
    Medals 0

    Sorry, for not being proper, but how would I get P(fool but not thief) and P(thief but not fool) if the event that Joe is a thief and Joe is a fool overlap?

    • one year ago
  7. apple_pi
    Best Response
    You've already chosen the best response.
    Medals 0

    OK to get P(fool not thief) get P(fool) = 0.6, P(not thief) = 1- P(thief) = 0.3 now multiply the two to get P(fool not thief). Do similarly for the other one. Then just add the two probabilities. Sorry but I have to go now.

    • one year ago
  8. windsylph
    Best Response
    You've already chosen the best response.
    Medals 0

    It's okay, thank you for your help.

    • one year ago
    • Attachments:

See more questions >>>

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.