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Homework Help: Coin flip Probability

  1. Aug 18, 2011 #1
    Question 1:
    A coin is flipped 4 times. Find the probability that it lands heads twice.

    Question 2:
    Four coins are flipped simultaneously. Find the probability that exactly two of the land on heads

    For the first one I made an H and T chart and got 6/16.

    The second one im thinking its the same thing.

    My question is how is the second question any different from the first?
  2. jcsd
  3. Aug 18, 2011 #2


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    Homework Helper

    Different questions, but same answer. You could get a different answer if the events were dependent on each other. However, tossing the coin doesn't affect the future coin tosses and you can treat it as tossing four coins at once. The fact that these are independent events is key.


    I noticed something about question 1. Is it asking for the probablility of exactly 2 heads or at least 2 heads? If at least 2 heads, then you would get a different answer.
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