At a gathering at which bankers, athletes, and lawyers are present, all of the bankers are athletes and none of the l...

Jacob-R on December 13, 2018

I’m happy to help. As always, let’s start with the question stem. It is a must be true question. In order to know what must be true, we have to understand the argument:

If B, A, and L ==>

B -> A (contrapositive not A -> not B)
AND
L -> not B (contrapositive B -> not L)

Remember, we know that bankers, athletes, and lawyers are all present. So there will be at least one banker, and we know from rule 1 that that banker is also an athlete. And we know from the contrapositive of rule 2 that that banker is not a lawyer. So at least one athlete is not a lawyer, which is answer C.

E is incorrect because we could hypothetically have a lawyer who is an athlete and that wouldn’t violate any of the rules or contrapositive, so “none of the lawyers are athletes” need not be true.

I hope that helps! Please let us know if you have further questions.

Zaviea-Gaynor on January 9, 2019

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