Unless

msirchia

I'm still unclear on why I am to negate sufficient when I come across unless, or should it just introduce the necessary condition?

"K cannot be selected for honor roll, unless H is selected to honor roll."

would I take H selected and move it to the sufficient and negate it?

/H ---->/K or contrapositive K----->H

or would it simply be

K----->H right from the start and have the "unless" introduce the necessary?

Please Help!!!

JustDoIt

Pick either H or K and make it the sufficient. It doesn't matter which one because which ever you pick and negate, the other will become the contrapositive.

Let's Pick H.

H is now sufficient.
Negate it (/H)
Put the other term in the necessary (/K)
/H -> /K

Now lets pick K.

K is now sufficient
Negate it (//K = K)
Put the other term in the necessary (H)
K -> H.

Hope this helps!