Q4) A radio system has a main antenna that has a reliability of 0.98. The radio has a backup antenna that is used if the main antenna fails, the reliability of the backup is 0.86. What is the overall reliability of the radio system? Q5) A desk fan has two primary parts. Part one has a reliability of 0.76 and part two has a reliability of 0.89. The engineers of the desk fan have included a backup for part one that also has a reliability of 0.76. What is the reliability of the desk fan? Q6) A solar power system comprises two key elements. The solar panels have a reliability of 0.96, and the energy storage system has a reliability of 0.90. As a precaution, engineers have included a backup for the energy storage system with a reliability of 0.82. What is the overall reliability of the solar power system?