Question 1

All red are yellow. No yellow is blue. Some blue are green. I. Some green are red. II. No green is red.

Accepted Answer

Solution: either I or II. The green outside blue may or may not meet red, and exactly one of the two must hold.

Question 2

Some shampoos are conditioners. All soaps are conditioners. I. At least some shampoos are soaps. II. Some shampoos are definitely not soaps.

Accepted Answer

Solution: either I or II. Every shampoo is either a soap or not, so at least one of the two is true; neither is forced.

Question 3

Some A are B. Some A are C. Some B are D. All C are B. I. Some A are D. II. Some D are C. III. No A is D.

Accepted Answer

Solution: either I or III. II is only possible; I and III are a Some/No pair about A and D.

Question 4

What are the common traps in Either-or conclusions questions?

Accepted Answer

One already follows: if "No bead is a gem" is definite, "either no bead is a gem or some beads are gems" is not the answer. All/No is not a pair.

Either-or conclusions

The idea