#20 - Local, Must Be True

[Dave Killoran]

Complete Question Explanation
(The complete setup for this game can be found here: lsat/viewtopic.php?t=9142)

The correct answer choice is (E)

If O is prescribed, then from the second rule M and O cannot be prescribed. Accordingly, answer choices (A) and (C) can be eliminated. Also, from our discussion of inferences, we learned that O and V cannot be prescribed together. Consequently, answer choices (B) and (D) can be eliminated. Thus, answer choice (E) is correct.

[lp1997]

If O is prescribed for a given case, which one of the following is a pair of treatments both of which must also be prescribed for that case?

My initial inference was that M and N must automatically be excluded because of the 1 dietary restriction rule. (This eliminated answer choices A and C) However, I could not figure out anything else from there using any inferences, so I ended up creating several hypotheticals. Are there any inferences that I am missing that could have made the process quicker?
Thanks.

[Jonathan Evans]

Hi, NSchlesi,

Good question. A lot of this game hinges on observing the interactions between the kinds of items selected and not selected, as you did here. Once you exclude M and N, let's see what else happens.

• M V

This rule (the contrapositive of the sixth rule) allows you to fill in the rest of the blanks.

• Selection: O __ __ __ __ Not Selected: M N V __

Remember that we have exactly one Dietary Regimen and either one or two Antibiotics. If we have a maximum of two Antibiotics, we must have a minimum of two Physical Therapies:

• Selection: D A A PT PT Not Selected: D D PT A

In this problem we know that one of the physical therapies is not prescribed. This means that the other two must be prescribed. Let's see where this takes us:

• Selection: O U W __ __ Not Selected: M N V __

Once we know that both U and W are prescribed, what else do we know?

• W F

We know F is not prescribed:

• Selection: O U W __ __ Not Selected: M N V F

Therefore the other two Antibiotics must be prescribed:

• Selection: O U W G H Not Selected: M N V F

This allows us to get the correct answer, (E), U and W.

[nschlesi]

Thanks Jonathan,
Just came back to this game almost 2 months of studying later and I'm thankful to have made some major improvements because of you guys.