Question 1194278
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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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<pre>
    P(selecting a blue or green marble) = P(selecting a blue marble) + P(selecting a green marble) =

                                        = {{{7/20}}} + {{{9/20}}} = {{{(7+9)/20}}} = {{{16/20}}} = {{{4/5}}} = 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.
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