Some epicures are ungenerous;
All my uncles are generous.
My uncles are not epicures.

Univ. “persons”; m = generous; x = epicures; y = my uncles.


Some x are m′.
All y are m.
All y are x′.


∴ Some x are y′.

Hence proposed Conclusion is wrong, the right one being “Some epicures are not uncles of mine.”

5.

Gold is heavy;
Nothing but gold will silence him.
Nothing light will silence him.

Univ. “things”; m = gold; x = heavy; y = able to silence him.


All m are x;
No m′ are y.
No x′ are y.


∴ No x′ are y.

Hence proposed Conclusion is right.

6.