A vendor’s distributed storage system was put into operation for 100 days, running 24 hours a day. 10th day

A failure occurred at noon, and it took 1 hour to recover from the failure. A failure occurred in the morning of the 25th day, and it took 4 hours to recover from the failure. 80th

One failure occurred in the morning, and it took 1 hour to recover from the failure. The availability of the software system is ()