December 2017 LSAT Section 1 Question 18

If the standards committee has a quorum, then the general assembly will begin at 6:00 P.M. today. If the awards commi...

josettebrooksbank on June 7, 2020

Difference between B & E?

Can you explain what the difference between B & E is? I was debating between these two and chose E as my answer, but I don't really understand how they are different. Since they both say that if one of the Quorum's happens then the other doesn't, it seems like they are just opposites of each other.

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SamA on June 8, 2020

Hello @josettebrooksbank,

Here is my diagram of our two statements.

SCQ ---> A6

ACQ ---> A7

First, let's discuss B. Here is the problem. The stimulus never stated that one of these quorums must occur. B would be correct if the stimulus said, "Either the standards committee has a quorum, or the awards committee has a quorum." In that case, we could conclude: not SCQ ---> ACQ. However, it is possible that neither quorum occurs.

As it stands, there is no conclusion that we can draw from "not SCQ." This is negating the sufficient condition, which has no effect on the necessary. This is why B is incorrect.

E is different, because it tells us that one of the quorums does occur. What is the result of a standards committee quorum? Consult the diagram.

SCQ ---> A6

The assembly will begin at 6. We can take this to mean that the assembly does not begin at 7. Consider the contrapositive of our second statement.

not A7 ---> not ACQ

There will be no awards committee quorum. This is why E is correct.

josettebrooksbank on June 10, 2020

ok perfect thank you!

on June 13, 2020

Because these are 2 conditional statement, how can I guarantee that there must be at least one quorum, if one or the other is absent?