Final answer:
The probability that the system functions, requiring both A and B to function, is calculated using the formula for the probability of either event occurring. By rearranging and substituting the given probabilities, we find that the probability the system functions is 0.94.
Step-by-step explanation:
Calculation of System Functionality Probability
To determine the probability that the system functions, we need to find the joint probability that both A and B function, denoted as P(A AND B). Given that the probability A functions is 0.98, and B functions is 0.95, we use the given that the probability either A or B functions (which includes the case where both function) is 0.99.
We start with the formula for the probability that either A or B functions, which is:
P(A OR B) = P(A) + P(B) − P(A AND B)
.
We can rearrange this to solve for P(A AND B):
P(A AND B) = P(A) + P(B) − P(A OR B)
.
Substituting the given probabilities, we get:
P(A AND B) = 0.98 + 0.95 − 0.99 = 0.94
.
Therefore, the probability that the system functions, which requires both A and B to function, is 0.94.