[ouid]

He misremebered the third task as well, since his solution to it, as stated, is wrong. If you aren't given that every card has a number on one side and a color on the other, then you need to check everything which does not satisfy the consequent.

[mlajtos]

I added "We have cards with a number and color on each face." to the task statement. Hope this makes rules clearer as I could not phrase it better.

[ouid]

The rules were clear before, what has changed is that they are now different rules. You were just wrong before.

You've still got a problem though, now when you ask the reader to verify the rule, you have to explicitly state that they're not trying to verify the first rule.

[mlajtos]

Oh shit, you are right. Added a completely explicit statement under the problem question. In both situations.

Thank you for pointing this out.