What does this equation mean?

A robot’s usable hours depend on a different variable: duty cycle, the fraction of the 8,760-hour year a unit spends actually working rather than charging, undergoing maintenance, or switching tasks — run here across the same 90/70/50 percent grid this series applies throughout, giving 7,884, 6,132, and 4,380 operating hours per unit per year respectively. Solving the labor-hours ledger, $F = \frac{L \times H_w}{H_r}$. for fleet size F across all nine combinations of the labor-force total L , the hours-worked bracket $H_w$ , and the duty-cycle-adjusted operating hours $H_r$ , produces a range from about 0.76 billion units (90 percent duty cycle, 1,600 hours worked) to about 1.88 billion units (50 percent duty cycle, 2,200 hours worked), with a representative central case — 70 percent duty cycle, 1,750 hours worked — landing at roughly 1.07 billion units. That is the identical nine-scenario grid this series’ opening entry already published, reproduced here from the same primary inputs checked fresh rather than a new range of its own. Every cell in that grid sits at least eight times below the post’s sixteen billion, several cells above twenty times below it — the same order-of-magnitude gap this series’ opening entry already established.