Answer: Our required probability is 0.0690.
Step-by-step explanation:
Since we have given that
Probability that seniors who do go on to a career in physics still fail the test P(F|P) = 60%
Probability that seniors who do not go to a career in physics fail the test = 1-0.6=0.4=40%
Probability that senior physics majors in fact go on to a career in physics = P(P) = 90%
Probability that he will not go on to a career in physics given that he fail the test is given by
[tex]\dfrac{P(F|P')\times P(P')}{P(F)}\\=\dfrac{0.4\times 0.10}{0.4\times 0.1+0.6\times 0.9}\\\\=\dfrac{0.04}{0.04+0.54}\\\\=\dfrac{0.04}{0.58}\\\\=0.06896\\\\\approx 0.0690[/tex]
Hence, our required probability is 0.0690.