Investigate the residual from a higher electricity block
A statement charges 0.20 for the first 300 kWh and 0.35 for additional units. Using the first-block rate as a flat reference leaves the extra tier charge in the Detective’s residual.
Open CalculatorInputs and calculation
| Tool input | Value |
|---|---|
| Currency | USD |
| Utility | Electricity (kWh) |
| Previous usage | 280 |
| Current usage | 340 |
| Previous flat rate (USD/unit) | 0.2 |
| Current flat rate (USD/unit) | 0.2 |
| Previous bill (USD) | 66 |
| Current bill (USD) | 84 |
Usage: (340 − 280) × 0.2 = 12. Rate: 340 × (0.2 − 0.2) = 0. Actual bill difference: 84 − 66 = 18. Residual: 18 − (12 + 0) = 6. All effects are in USD.
Tool result · USD 18.00
| Tool input | Value |
|---|---|
| Currency | USD |
| Utility | Electricity (kWh) |
| Previous usage | 280 |
| Current usage | 300 |
| Previous flat rate (USD/unit) | 0.2 |
| Current flat rate (USD/unit) | 0.2 |
| Previous bill (USD) | 66 |
| Current bill (USD) | 70 |
Usage: (300 − 280) × 0.2 = 4. Rate: 300 × (0.2 − 0.2) = 0. Actual bill difference: 70 − 66 = 4. Residual: 4 − (4 + 0) = 0. All effects are in USD.
Tool result · USD 4.00
What the comparison shows
The separately known schedule explains the residual: 40 × (0.35 − 0.20) = 6. This conclusion relies on the tariff, not on the residual alone.
Assumptions and limits
The Detective uses flat-rate decomposition. Rebuild the statement with the bill calculator to model tiers directly.