The probability of two events A and B happening simultaneously is 0.17. The probability of only event A happening is 0.34. Find the probability of event B happening, if event A has already happened

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Answer:

because is the probability is 0.17 and 0.34 is fair

You can use the multiplication rule of probability.

The probability of event B happening if event A has already happened is 0.5

What does general multiplication rule of probability says for 2 events A and B?

[tex]P( A \: \rm and \: B) = P(A)P(B|A) = P(B)P(A|B)[/tex]

Since we've to find the probability of B given that A has already happened, we need [tex]P(B|A)[/tex]

Since the probability of both event A and event B happening simultaneously is 0.17, thus:
[tex]P(A \: \rm and \: B) = 0.17\\ [/tex]

Since the probability of only event A happening is 0.34, thus:

[tex]P(A) = 0.34[/tex]

Thus, from the multiplication rule, we have:
[tex]P(A \: \rm and \: B) = P(A)P(B|A)\\ 0.17 = 0.34 \times P(B|A)\\\\ \dfrac{0.17}{0.34} = P(B|A)\\\\ P(B|A) = \dfrac{1}{2} = 0.5[/tex]

Thus, we have the probability of event B happening when A has already happened as 0.5

Learn more about multiplication rule of probability here:

https://brainly.com/question/14450597