Before a software package is launched, it is subject to four independent error tests

Statistics Nov 18, 2020

Before a software package is launched, it is subject to four independent error tests. If there is an error, the first test will find it with probability 0.4, the second test will find it with probability 0.3, and the third and fourth tests will discover it each with probability 0.2. If the program contains an error, what is the probability that it will be found?