(11-15) : (i) All erasers are sharpeners → Universal Affirmative (A-type). (ii) Some pencils are pens → Particular Affirmative (I-type). (iii) No eraser is a pen → UniversalNegative (E-type). (iv) Some erasers are not pens → Particular Negative (O-type). (11-12) : All erasers are sharpeners. All sharpeners are pencils. A + A ⇒ A - type of Conclusion “All erasers are pencils.” (P) All sharpeners are pencils. Some pencils are pens. A + I ⇒ No Conclusion All erasers are pencils. Some pencils are pens. A + I ⇒ No Conclusion 11. (3) Conclusions I and II form Complementory Pair. Therefore, either Conclusion I or Conclusion II follows.