An electronic assembly consists of subsystems A and B Record

An electronic assembly consists of subsystems A and B. Records on 100 preliminary checkout tests show that Subsystem A failed 10 times, Subsystem B alone failed 15 times and both subsystems failed together 5 times. What is the probability that Subsystem A fails alone?

Solution

If subsystem A failed 10 times and both failed together 5 times, then subsystem A failed alone 5 times.

Using the formula P(E) = frequency of E/number of trials of experiment,

Probability that subsystem A fails alone = 5/100 = 1/20 or 0.05 (answer)