Respuesta :
Answer:
0.305 = 30.5% probability that a randomly chosen student took Form B and did not pass
Step-by-step explanation:
Conditional Probability
We use the conditional probability formula to solve this question. It is
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]
In which
P(B|A) is the probability of event B happening, given that A happened.
[tex]P(A \cap B)[/tex] is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: Took Form B.
Event B: Did not pass.
Half of a class took Form A of a test, and half took Form B.
This means that [tex]P(A) = 0.5[/tex]
Of the students who took form B, 39% passed.
So 100 - 39 = 61% did not pass, which means that [tex]P(B|A) = 0.61[/tex].
What is the probability that a randomly chosen student took Form B and did not pass?
[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]
[tex]P(A \cap B) = P(B|A)*P(A) = 0.61*0.5 = 0.305[/tex]
0.305 = 30.5% probability that a randomly chosen student took Form B and did not pass
