Answer:
0.2
Step-by-step explanation:
Let P(A) = probability of first alarm failing and P(B) = probability of second alarm failing = 0.05. Since the events are independent, we have that the probability of both alarms failing or of system failure is P(A ∪ B) = P(A) × P(B).
Since the probability of both alarms failing or of system failure, P(A ∪ B) = 0.01, then the probability of the first alarm failing P(A) = P(A ∪ B)/P(B) = 0.01/0.05 = 0.2.
So, the probability of the first alarm failing P(A) = 0.2
