A smoke-detector system uses two devices, A and B. If smoke is present, the probability that it

Question:

A smoke-detector system uses two devices, A and B. If smoke is present, the probability that it will be detected by device A is .95; by device B, .98; and by both devices, .94.
a. If smoke is present, find the probability that the smoke will be detected by device A or device B or both devices.
b. Find the probability that the smoke will not be detected.