Hello,

I am struggling with compound contrapositives. I know that when negating, you also have to switch the and/or. However, what about the use or absence of "but not both"?

Example from February 1999, link provided at bottom:

Two conditions within the problem are listed below:

If yews are not in the park, then either laurels or oaks, but not both, are in the park.

Original: ~Y-----> L or O

Contrapositive: ~L and ~O -----> Y.

If it is not the case that the park contains both laurels and oaks, then it contains firs and spruces.

Original: ~L and ~O ----> F and S

Contrapositive: ~F and ~S. -----> L or O

This second rule doesn't include the "but not both" but it seems to diagram the contrapositive regardless of the "but not both" piece's inclusion.

[Deleted: Do not post LSAT questions, any copyrighted content, or links to content that infringe on copyright.]

Thank you,

Lindsay