Question 1046226: The probability that traffic lights on a certain road will be green is 0.6. When a driver on that road approaches two traffic lights in a row, X is the number of traffic lights that are green.
What is P(X=1) as a decimal?
Answer by robertb(5830)   (Show Source):
You can put this solution on YOUR website! There are only three possible mutually exclusive cases here:
{red},
{green, red}, and
{green, green}.
These can be illustrated also using a tree diagram.
P({red}) = 0.4,
P({green, red}) = 0.6*0.4 = 0.24, and
P({green, green}= = 0.6*0.6 = 0.36.
P(X=1) = P({green, red}) = 0.24.
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