There have been some failures of the company's internal facing website. A security engineer has found the WAF to be the root cause of the failures. System logs show that the WAF has been unavailable…

92.24 percent would require roughly 56 hours of downtime, far exceeding the stated 14 hours and does not correspond to any valid interpretation of the given figures.

98.06 percent results from dividing all 14 hours (including scheduled maintenance) by 722 without excluding planned downtime: (722 - 14) / 722, which misapplies MTTR methodology.

Of the 14 total downtime hours, 2 hours were scheduled maintenance and are excluded from unplanned downtime, leaving 12 hours of unplanned outage across 3 incidents (MTTR = 4 hours). Uptime is then (722 - 12) / 722 = 710 / 722 = 98.34 percent, which correctly applies the MTTR methodology by separating planned from unplanned unavailability.

99.72 percent would imply only about 2 hours of downtime, which matches only the scheduled maintenance window and ignores the 12 hours of unplanned outages entirely.