Suppose every fth person in the world suers from Ebola virus disease. A test is administered which detects a disease nine times out of ten,

Suppose every fifth person in the world suffers from Ebola virus disease. A test is administered which detects a disease nine times out of ten, but also tests positive for three out of ten healthy people. All people who test positive are given a drug that produces a special rash for every fourth person. Suppose a randomly chosen test subject develops the special rash. What is the probability that the person had Ebola virus disease?