SOLUTION: Suppose a certain traffic light shows a red light for 42 seconds, a green light for 45 seconds, and a yellow light for 5 seconds.
If you look at this light at a randomly chosen
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-> SOLUTION: Suppose a certain traffic light shows a red light for 42 seconds, a green light for 45 seconds, and a yellow light for 5 seconds.
If you look at this light at a randomly chosen
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Question 1022861: Suppose a certain traffic light shows a red light for 42 seconds, a green light for 45 seconds, and a yellow light for 5 seconds.
If you look at this light at a randomly chosen instant, what is the probability that you see a red or yellow light? (Enter your probability as a fraction.)
You can put this solution on YOUR website! By the addition law, P(R or Y) = P(R) + P(Y) - P(R and Y).
But R and Y are mutually exclusive events, so P(R and Y) = 0.
==> P(R or Y) = P(R) + P(Y) = 42/92 + 5/92 = 47/92.
