The figure below is a representation of a system comprised of two subsystems that are said to operate in parallel. Each subsystem has two components that operate in series (refer to Exercise 3.81).The system will operate properly as long as at least one of the subsystems functions properly.

The probability of failure for each component in the system is .l. Assume the components operate independently of each other.

a. Find the probability that the system operates properly.

b. Find the probability that exactly one subsystem fails.

C. Find the probability that the system fails to operate properly.

d. How many parallel subsystems like the two shown here would be required to guarantee that the system would opcrate properly at least 99% of the time?