Z Virus
Discrete Mathematics
Level
1
The world had been harmed by a widespread Z-virus, which already turned 10% of the world's population into zombies.
The scientists then invented a test kit with the sensitivity of 90% and specificity of 70%: 90% of the infected people will be tested positive while 70% of the non-infected will be tested negative.
If the test kit showed positive result, what would be the probability that the tested subject was truly zombie?
If the solution is in a form of \(\dfrac{a}{b}\), where \(a\) and \(b\) are coprime positive integers, submit your answer as \(a+b\).
by
Worranat Pakornrat