# Stuck on Logic Games: How does 'OR' equal 'BOTH'

• January 16, 2016 at 5:26 pm #1345
tringo335
Participant

Hello Fellow Lsatters!

I’m currently on chapter 13 of the LSAT Trainer (shoutout to Mike Kim for such a helpful book!) and my brain will not allow me to understand the concept of “Or” in logic games including the possibility of “both” (mentioned on page 177 of the LSAT Trainer).  I remembered the concept on the practice diagram on page 183 but got both questions wrong because I assumed that both “M” as well as “J” made the olympic team (since the rule was J OR M–> F). I took the OR in the diagram to mean both and got in as page 177 suggested and got it wrong. Can someone please clarify? *Many, Many thanks :)*

• January 16, 2016 at 5:55 pm #1346
dannypearlberg
Participant

If it says ‘A or B’, this means that it is possible to have both A and B, but you don’t automatically have both of them in. The situation that ‘A or B’ rules out is the situation where neither of them are in.

If it says ‘A or B but not both’, this means that one of them is in, but you can’t have both in and you can’t have both out.

On page 183, when it says “If J or M, then F”, this is a conditional rule: If we have J, or M, then F is in as well. But if we have J, this rule tells us nothing about whether or not we have M, and likewise if have M, this rule tells us nothing about whether or not we have J.

When it says “Either H or I, but not both”, this means that either H is in, or I is in, but you can’t have both H and I in, and you can’t have both H and I out.

Hope that helps 🙂

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