Question

Marley drives to work every day and passes two independently operated traffic lights. the probability that both lights are red is 0.35. the probability that the first light is red is 0.48. what is the probability that the second light is red, given that the first light is red?

Answer 1

This is a conditional probability problem.

Let E be probability that the second light is red, given that the first light is red.

Let F be the probability that the first light is red, which is = 0.48,

therefore

P(E | F) = P(EF) / P(F)

= 0.35 / 0.48

= 0.73

Therefore, the probability that the second light is red, given that the first light is red is 0.73