Question 1
Statements:
No essential is a useful.
All sustainable are useful.
Conclusions:
I. No useful is a essential.
II. No sustainable is a essential.
III. Some useful are not essential.
Immediate vs Mediate Inference:
Immediate Inference: Direct conversion from one statement
Mediate Inference: Deduction requiring multiple statements
Checking Each Conclusion:
✓ Conclusion I: "No useful is a essential" - IMMEDIATE INFERENCE
Conversion of "No essential is a useful" - FOLLOWS
✓ Conclusion II: "No sustainable is a essential" - MEDIATE INFERENCE
All C are B (A) + No B is A (E) = A + E = E - FOLLOWS
✓ Conclusion III: "Some useful are not essential" - IMMEDIATE INFERENCE
From "No A is B", definitely some B are not A - FOLLOWS
Answer: All conclusions I, II and III follow
Immediate Inference: Direct conversion from one statement
Mediate Inference: Deduction requiring multiple statements
Checking Each Conclusion:
✓ Conclusion I: "No useful is a essential" - IMMEDIATE INFERENCE
Conversion of "No essential is a useful" - FOLLOWS
✓ Conclusion II: "No sustainable is a essential" - MEDIATE INFERENCE
All C are B (A) + No B is A (E) = A + E = E - FOLLOWS
✓ Conclusion III: "Some useful are not essential" - IMMEDIATE INFERENCE
From "No A is B", definitely some B are not A - FOLLOWS
Answer: All conclusions I, II and III follow