[tex] P(\text{stop at first light signal}) = 0.4 = P(A) [/tex](adsbygoogle = window.adsbygoogle || []).push({});

[tex] P(\text{stop at second light signal}) = 0.5 = P(B) [/tex]

[tex] P(\text{stop at least one of two signals}) = 0.6 = P(A \cup B) [/tex]

Then [tex] P(A \cap B) = P(A) + P(B) - P(A \cup B) = 0.3 [/tex]

[tex] P( \text{first signal but not second}) = P(A \cap B') = 1-0.3 = 0.7 [/tex]

[tex] P(\text{exactly one signal}) = P(A \cup B) - P(A \cap B) = P(A \Delta B) = 0.3 [/tex]

Are these correct?

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# More Probability problems

**Physics Forums | Science Articles, Homework Help, Discussion**