Language of question ("Must be false" w/ neither/nor answrs)

[brian.atchley]

I have a question about how to interpret the language of a particular question from the LSAT Interact Session 6 Open Conditional Grouping: Borne Airport Game, Q4

"If R is used for commercial planes, then which one of the following must be false?"

How is the statement "Neither S nor V is used for commerical planes" not false? In other words, why isn't this a correct answer for the question stem in that it must be false?

Because if R is used for commercial planes, S has the ability to be used as a commercial plane thus rendering the statement "neither S nor V is used for commercial planes" false. This statement (answer A) must be false, right?

I want to understand this double negative type of tricky language...

[ManhattanPrepLSAT1]

Good question Brian! Your hypothetical shows that answer choice (A) could be false, but not that it must be false. Isn't it also possible to use S and V for private planes? If so, that would show that answer choice (A) could be true!

I'm trying to make the point that answer choice (A) could be true, it could be false--we simply don't know!

We know that V is used for private planes on Q4--we can infer that from the conditional information. For the negative language, try translating it into something positive: neither S nor V is used for commercial planes (i.e., both S and V are used for private planes).

Hope that helps!