A network has three independent file servers, each with 90 percent reliability. The probability that the network will be functioning correctly (at least one server is working) at a given time is:
A)99.9 percent.
B)97.2 percent.
C)95.9 percent.
D)72.9 percent.

Question

Quizplus · Accepted Answer

The probability that all three servers fail simultaneously is (1 - 0.9)^3 = 0.1^3 = 0.001 or 0.1%. Therefore, the probability that at least one server is working is 1 - 0.001 = 0.999 or 99.9%.

A Network Has Three Independent File Servers, Each with 90