SOLUTION: A marble is randomly selected from a bag of solid-colored marbles. The probability of selecting a blue marble is 7/20. The probability of selecting a green marble is 9/20. What is

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Question 1194278: A marble is randomly selected from a bag of solid-colored marbles. The probability of selecting a blue marble is 7/20. The probability of selecting a green marble is 9/20. What is the probability of selecting a blue or green marble?
Answer by ikleyn(52788) About Me  (Show Source):
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A marble is randomly selected from a bag of solid-colored marbles.
The probability of selecting a blue marble is 7/20.
The probability of selecting a green marble is 9/20.
What is the probability of selecting a blue or green marble?
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    P(selecting a blue or green marble) = P(selecting a blue marble) + P(selecting a green marble) =

                                        = 7%2F20 + 9%2F20 = %287%2B9%29%2F20 = 16%2F20 = 4%2F5 = 0.8 = 80%.

These events, selecting a blue marble and selecting a blue marble are disjoint, or mutually exclusive events,
so the probability to have one of the two events is the sum of particular probabilities.