Question 13

Scenario: The route used by a certain motorist in commuting to work contains two intersections with traffic signals.

Events:

  • - Stop at the first signal.
  • - Stop at the second signal.

Probabilities:

  • .
  • .
  • .

(a)

Problem: What is the probability that he must stop at both signals?

Process: ...

Answer: 0.2.

(b)

Problem: What is the probability that he must stop at the first signal but not at the second one?

Process: ...

Answer: 0.25.

(c)

Problem: What is the probability that he must stop at exactly one signal?

Process: ...

Answer: 0.60.