She cannot take Japanese if she takes Macroeconomics.
Started by
mamie
· started 2019-12-24 01:10
· last activity 2020-01-03 17:35
· 1 reply
I am wonder how you knew that this rule is a "not both" rule and that it should only be put in the "out" pile?
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SamA
· 2020-01-03 17:35
Hello @mamie,
"She cannot take Japanese if she takes Macroeconomics."
This rule basically tells us that Japanese and Macroeconomics cannot coexist. They may both be out, but they cannot both be in. I will demonstrate.
"If she takes Macroeconomics" is our sufficient condition. "Cannot take Japanese" is necessary.
M - - - - - - - - > not J
Now let's look at the contrapositive.
J - - - - - - - - -> not M
We now know that one of the three spaces in our out-group must be reserved for either J or M.
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