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I have a question in my math class in college. Here is the question, but I just need help on HOW to answer it. My text isn't clear at all.
A box contains 2 black balls and 3 gold balls. 2 balls are randomly drawn in succession.
a.if there is no replacement, what is the probablity that both balls are black?
b.if there is a replacement before the second draw, what is the probablitity that both balls are black?
My classes are online, and the text is very confusing and the equations for probability all seem to be exactly the same. Please help! Thanks.

  • math -

    a) prob = (2/5)(1/4) = 2/20 = 1/10

    b) prob = (2/5)(2/5) = 4/25

  • math -

    So I just multiply the probability of each ball on each turn? Thank you sooo much! Why can't the text just say that?

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