If all plinks are plonks and some plunks are plinks, which of these statements must be true?

X: All plinks are plunks.
Y: Some plonks are plunks.
Z: Some plinks are not plunks.

Source: Crux Mathematicorum, 2004:

We know that some plunks are plinks. Since all plinks are plonks, those plunks must also be plonks. Then, some plonks are plunks. Therefore, Y is true.

Posted by Math Man on 2021-04-08 13:47:53