SOLUTION: A can contains 7 pink balls and 5 blue balls. FOUR balls are selected without replacement. What is the probability of 1) all pink or all blue 2) exactly 3 pink 3) at least 3 pink

Question 177396: A can contains 7 pink balls and 5 blue balls. FOUR balls are selected without replacement. What is the probability of 1) all pink or all blue 2) exactly 3 pink 3) at least 3 pink 4) exaclty 3 pink of 3 blue. I am studying "Adding Probabilites" and I just don't get it?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A can contains 7 pink balls and 5 blue balls.
FOUR balls are selected without replacement.
What is the probability of
1) P(all pink or all blue) = (7C4 + 5C4)/12C4
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2) P(exactly 3 pink) = 7C3*5C1/12C4
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3) P(at least 3 pink) = P(3 pink) + P(4 pink) = [7C3*5C1]/12C4 + 5C4/12C4
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4) P(exactly 3 pink or 3 blue) = P(3 pink) + P(3 blue)
= 7C3*5C1/12C4 + 5C3*7C1/12C4
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Cheers,
Stan H.
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