Under the revised regulations of the Global Mineral Oversight Commission, any rare-earth mining facility operating in Zone 4 that extracts dysprosium is required to undergo a quarterly heavy-metals soil audit. Furthermore, every mining facility that undergoes a quarterly heavy-metals soil audit is automatically awarded an Eco-Compliance Certificate by the commission. Facility Alpha operates in Zone 4, but it has not been awarded an Eco-Compliance Certificate by the commission.
If the statements above are true, which of the following must also be true based on them?
- Facility Alpha does not extract dysprosium.Cevap
- BFacility Alpha underwent a quarterly heavy-metals soil audit but failed to meet the required environmental safety standards.
- CIf a mining facility has been awarded an Eco-Compliance Certificate, that facility must extract dysprosium.
- DFacility Alpha extracts rare-earth elements other than dysprosium at its Zone 4 location.
- ENo mining facility operating outside of Zone 4 is required to undergo a quarterly heavy-metals soil audit.
Cevap
Facility Alpha does not extract dysprosium.
Combining the premises yields the conditional rule: if a facility operates in Zone 4 and extracts dysprosium, it receives an Eco-Compliance Certificate. The contrapositive dictates that if a facility lacks an Eco-Compliance Certificate, it either does not operate in Zone 4 or does not extract dysprosium. Because the stimulus explicitly states that Facility Alpha does operate in Zone 4, it must logically follow that Facility Alpha does not extract dysprosium.
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Identifying Must-Be-True Statements and Valid Deductions