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    A game is made in which you have to hit a moving target, with an air rifle.
    a player has up to 3 pellets in a round. 5 points are scored if a target is hit, but the round is over if missed.

    J has a constant probability of 0.4 of hitting the target.

    X is the random variable, no. of point scored in a round.

    a.find the probability that J gets 15 points in a round. I got 0.064
    b.find the probability distribution of x. when x=0. i got 0.6
    x=5, 0.24
    x=10, 0.096
    x= 15, 0.064
    A game consists of 2 rounds.

    c. find the probability that J scores more on the 2 round that the first.

    I have no idea on how to answer c, any help is appreciated. Thanks
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    (Original post by Hi, How are you ?)
    A game is made in which you have to hit a moving target, with an air rifle.
    a player has up to 3 pellets in a round. 5 points are scored if a target is hit, but the round is over if missed.

    J has a constant probability of 0.4 of hitting the target.

    X is the random variable, no. of point scored in a round.

    a.find the probability that J gets 15 points in a round. I got 0.064
    b.find the probability distribution of x. when x=0. i got 0.6
    x=5, 0.24
    x=10, 0.096
    x= 15, 0.064
    A game consists of 2 rounds.

    c. find the probability that J scores more on the 2 round that the first.

    I have no idea on how to answer c, any help is appreciated. Thanks
    Here is a start

    Scores 5 in first round and then more in the next round = 0.24 x (0.096+0.064)

    Does that help
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    (Original post by TenOfThem)
    Here is a start

    Scores 5 in first round and then more in the next round = 0.24 x (0.096+0.064)

    Does that help
    I see that in the first round, if you only score 5 points, that a probability of 0.24, but I don't see why you multiplied by (0.096+0.064)
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    (Original post by Hi, How are you ?)
    I see that in the first round, if you only score 5 points, that a probability of 0.24, but I don't see why you multiplied by (0.096+0.064)
    Because you want him to score more than 5 in the second round
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    (Original post by TenOfThem)
    Because you want him to score more than 5 in the second round
    so to get more that 5, you add the probabilities of 10 and 15, as they are higher and so the probabilities are (0.096+0.064), then you times them.

    Ok, what should i do next?
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    (Original post by Hi, How are you ?)
    so to get more that 5, you add the probabilities of 10 and 15, as they are higher and so the probabilities are (0.096+0.064), the you times them.

    Ok, what should i do next?
    Consider the other options (other than 5 in the first round)
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    (Original post by TenOfThem)
    Consider the other options (other than 5 in the first round)
    could score 10 in first round, then 15 in next so, 0.096 x 0.064, right?

    and those are the only options left?
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    (Original post by Hi, How are you ?)
    could score 10 in first round, then 15 in next so, 0.096 x 0.064, right?

    and those are the only options left?
    Is there nothing else that you can score in round one?
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    (Original post by TenOfThem)
    Is there nothing else that you can score in round one?
    Oh yeah, the 0, so its 0.6 X (0.096 + 0.064 + 0.24)
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    (Original post by Hi, How are you ?)
    Oh yeah, the 0, so its 0.6 X (0.096 + 0.064 + 0.24)
    indeed
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    (Original post by TenOfThem)
    indeed
    What shall I do next?
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    (Original post by Hi, How are you ?)
    What shall I do next?
    seriously?

    you have some viable options, what would you usually do with the probabilities to get the total probability
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    (Original post by TenOfThem)
    seriously?

    you have some viable options, what would you usually do with the probabilities to get the total probability
    Add, them?
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    (Original post by Hi, How are you ?)
    Add, them?
    yes
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    (Original post by TenOfThem)
    yes
    I see, 1 more q, why do you add them?
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    (Original post by Hi, How are you ?)
    I see, 1 more q, why do you add them?
    Why wouldn't you

    This is GCSE maths
    P(A and B) = P(A) x P(B)
    P(A or B) = P(A) + P(B) (if mutually exclusive)

    Imagine a tree diagram

    First branches are the score for round 1
    Second branches are More or Not

    You have multiplied along the branches to get (0, more) and (5, more) etc

    Then you add those probabilities

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    (Original post by TenOfThem)
    Why wouldn't you

    This is GCSE maths
    P(A and B) = P(A) x P(B)
    P(A or B) = P(A) + P(B) (if mutually exclusive)
    I see, makes sense. Thanks
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    (Original post by Hi, How are you ?)
    I see, makes sense. Thanks
    Did you see my edit

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