Dear co-listers. I was solving some exercises on probability topics, but
suddenly a doubt came to me when I tried to solve a problem.
The problem says that: Suppose that the probability of being sick of flu
during an epidemic is 0.6. The past experience has showed that certain serum
is effective in 80% of the times to avoid a person being sick of flu, if the
person is exposed to it. Two people, one inoculated and the other donít are
employees of a company. Suppose that they arenít in the same place, they are
not in contact with the same people and they canít be infected between each
other. What is the probability that at least one of them is affected by the
I make the following reasoning:
Non-inoculated sick, inoculated non-sick: 0.6 X 0.8 = 0.48
Non-Inoculated non-sick, inoculated sick: 0.4 X 0.2 = 0.08
Both Sick: 0.6 X 0.2 = 0.12
Answer: 0.68. I donít know if the procedure and reasoning are wrong, but the
textbook says that the answer (without explaing how they get it) is 0.5952.
Can somebody provide me advice to this respect?
Thanks for your kindly cooperation.
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