Answer: P(AUB) = 0.93 + 0.89 - 0.87 = 0.95
Therefore, the probability that at least one train is on time is 0.95.
Step-by-step explanation:
The probability that at least one train is on time is the probability that either train A, B or both are on time.
P(A) = P(A only) + P(A∩B)
P(B) = P(B only) + P(A∩B)
P(AUB) = P(A only) + P(B only) + P(A∩B)
P(AUB) = P(A) + P(B) - P(A∩B) ......1
P(A) = 0.93
P(B) = 0.89
P(A∩B) = 0.87
Then we can substitute the given values into equation 1;
P(AUB) = 0.93 + 0.89 - 0.87 = 0.95
Therefore, the probability that at least one train is on time is 0.95.