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anonymous

  • one year ago

Urn A has 16 white and 10 red balls. Urn B has 2 white and 9 red balls. We flip a fair coin. If the outcome is heads, then a ball from urn A is selected, whereas if the outcome is tails, then a ball from urn B is selected. Suppose that a red ball is selected. What is the probability that the coin landed heads?

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  1. anonymous
    • one year ago
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    @is3535

  2. is3535
    • one year ago
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    9 didve by 2=

  3. anonymous
    • one year ago
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    how'd you get 9/2? @is3535

  4. is3535
    • one year ago
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    Urn B has 2 white and 9 red balls

  5. anonymous
    • one year ago
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    9/2 is 4.5 @is3535

  6. is3535
    • one year ago
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    that your answer

  7. anonymous
    • one year ago
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    4.5?

  8. anonymous
    • one year ago
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    4.5? its asking the probability? @is3535

  9. anonymous
    • one year ago
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    @Leong @YoloShroom

  10. is3535
    • one year ago
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    oh im sry it will be 9

  11. is3535
    • one year ago
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    whic is biger 9 or 2

  12. anonymous
    • one year ago
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    9

  13. is3535
    • one year ago
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    yea

  14. is3535
    • one year ago
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    9 is your answer

  15. anonymous
    • one year ago
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    how? @is3535

  16. is3535
    • one year ago
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    Urn B has 2 white and 9 red balls. We flip a fair coin. If the outcome is heads, then a ball from urn A is selected, whereas if the outcome is tails, then a ball from urn B is selected. Suppose that a red ball is selected. What is the probability that the coin landed head,

  17. anonymous
    • one year ago
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    are we doing some ratio??? or like....

  18. is3535
    • one year ago
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    |dw:1444156898622:dw|

  19. anonymous
    • one year ago
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    its just saying, Suppose that a red ball is selected. What is the probability that the coin landed heads? @Leong

  20. anonymous
    • one year ago
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    4.5 :v you take 9 divide for 2, like you got less ball mean less chance.

  21. anonymous
    • one year ago
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    @dan815

  22. anonymous
    • one year ago
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    @Shalante

  23. Pulsified333
    • one year ago
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    Probability can not be more than 1

  24. anonymous
    • one year ago
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    okay :v then if not one we should do some ratio here: 10 over 16, means that 0.625 chance that the A get to choose :v

  25. anonymous
    • one year ago
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    i don't think thats right @Leong

  26. anonymous
    • one year ago
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    @BAdhi

  27. BAdhi
    • one year ago
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    This involves conditional probability and total probability theorem @vzforever are you familiar with them?

  28. anonymous
    • one year ago
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    yes @BAdhi

  29. BAdhi
    • one year ago
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    can you show me the given information written as the notation used in probability such as p(A) , p(B) etc

  30. anonymous
    • one year ago
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    i don't understand @BAdhi

  31. BAdhi
    • one year ago
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    can you write down the given information in the mathematical notation? for example probability of choosing A => P(A)

  32. anonymous
    • one year ago
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    Pr(A)= 1/2 Pr(B)= 1/2 @BAdhi

  33. anonymous
    • one year ago
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    what next? @BAdhi

  34. BAdhi
    • one year ago
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    what about the probability of getting a red ball given that we have choosen A? can you show it in the notation?

  35. anonymous
    • one year ago
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    Pr(AR)=10/26

  36. BAdhi
    • one year ago
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    umm, by P(AR) you mean \(P(A \cap R)\) ?

  37. anonymous
    • one year ago
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    no its 10/42 @BAdhi

  38. BAdhi
    • one year ago
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    10/42 is the probability of choosing a red ball out of all the balls.. but you see, since its already given that A has been choosen the amount of balls are reduced to 26. And i still need the answer to the previous question @vzforever

  39. anonymous
    • one year ago
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    whats ur previous question? @BAdhi

  40. BAdhi
    • one year ago
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    what do you mean by P(AR).. from what ive learned no such notation is used in prbability either it has to be \(P(A\cap R) , P(A\cup R), P(A|R)\) ??

  41. anonymous
    • one year ago
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    yes ur right

  42. anonymous
    • one year ago
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    what u said before was correct

  43. BAdhi
    • one year ago
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    ok.. what about the notation.. arent you going to answer my question?

  44. anonymous
    • one year ago
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    i said yes its (P(A \cap R)\)

  45. BAdhi
    • one year ago
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    \(P(A\cap R)\) means the probility of choosing a red ball and choosing A in here event -> choosing A and choosing red ball has still not occured but what i asked was, probability of choosing a Red ball given that A is choosen. in here A has already being chosen

  46. BAdhi
    • one year ago
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    so the correct notation is \(P(R | A)\)

  47. anonymous
    • one year ago
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    ok

  48. BAdhi
    • one year ago
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    similarly you can find P(B), P(R|B), P(W|B), P(W|A) so since the event -> turning head and the event -> choosing A are both same, what they are asking is, P(A|R)

  49. anonymous
    • one year ago
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    ok so is it (1/2)/(10/42)

  50. anonymous
    • one year ago
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    which is 5/42

  51. BAdhi
    • one year ago
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    so what you are saying is, \(P(A|R) = P(R)\times P(A)\) ??

  52. anonymous
    • one year ago
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    can you explain to me? i need to get this done.

  53. anonymous
    • one year ago
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    @kropot72

  54. BAdhi
    • one year ago
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    Its normal to get confused with the difference between \(P(A\cap R)\) and \(P(R|A)\) so I recommend you to read and look more into the explanation ive given in the previous post The definition of the conditional probability is, \(P(R|A) = \frac{P(R\cap A)}{P(A)}\) since P(R|A) and P(A) are known, you can find \(P(R\cap A)\) since what they are asking is P(A|R) , \(P(A|R) =\frac{P(A\cap R)}{P(R)} \) can \(P(A\cap R)\) is obtained in the previous step and hope you know how to find P(R)

  55. anonymous
    • one year ago
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    ok so what do i do to solve this problem

  56. anonymous
    • one year ago
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    we haven't even gotten there yet

  57. anonymous
    • one year ago
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    @TQKMB

  58. anonymous
    • one year ago
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    @BAdhi can we do the problem?

  59. BAdhi
    • one year ago
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    thats what im trying to do the whole time.. i dont wanna give you the answer straight forward, since itll be pretty useless. as a guidance let me state this, you have to find the values of the following variables from the given information straight forward P(A), P(R|A), P(R) with use of conditional probability definition (which ive given above) you have to find \(P(A\cap R)\) after that find P(A|R) with use of the same conditional probability definition (which is also given previously) what they are asking is the value of P(A|R)

  60. anonymous
    • one year ago
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    ok

  61. anonymous
    • one year ago
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    can u explain with numbers

  62. BAdhi
    • one year ago
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    it is really important to know the difference between P(A|R) and \(P(A \cap R) \) since , as you can see even in this problem they are applied so close together in problems Are you clear with the difference between them?

  63. BAdhi
    • one year ago
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    first give me what youve tried pls after that ill give the answer

  64. anonymous
    • one year ago
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    110/299 and 299/462 are the answers I've gotten and neither are right. obviously i need help cause idk what I'm doing. and I've made a tree

  65. anonymous
    • one year ago
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    @BAdhi

  66. anonymous
    • one year ago
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    @dan815

  67. BAdhi
    • one year ago
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    can you show the steps too.. that would be a good starter

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