by ManhattanPrepLSAT1 Mon Jul 05, 2010 10:42 pm
Really good questions, and ones that I think as you continue to prepare for the LSAT, you'll find are at the heart of the test.
Let's start with the 3rd and 4th constraints.
3. If F is selected, then Q must be selected.
4. If G is selected, then K must be selected.
Both of these constraints do not imply that F and Q are selected together and that G and K are selected together. Instead the "if" part implies the "then" part. So, if F is selected then Q must be, but if F is not selected, then we do not know anything about Q. Likewise, if G is selected then K must be selected, but if G is not selected, then we do not know anything about K.
15. If F is the chairperson of the committee
_ _ / _ _ _
tenets/homeowners
we can get a sense for how many tenets and how many homeowners from the second constraint.
If F is selected then
F _ / _ _ _
tenets/homeowners
We could not select J, M, nor G because each one of those would require that we have too many tenets. If J or M were selected we would need both, but we do not have room for two more tenets. Also, if G were selected, then we would need to select K, but again we do not have room for two more tenets. Since we can rule out J, M and G, the only tenet left that can be selected is K - answer choice (B).
19. The committee must include at least one representative from which one of the following pairs.
Answer choice (A) could be eliminated if you could find a hypothetical in which neither F not P were selected. So for each answer choice, see if you can have neither of the characters mentioned. For four of the answer choices you should be able to find solutions without any of the characters mentioned in the pairs. But for one for one of the pairs, you will not be able to find a hypothetical that satisfies all of the constraints with neither character - that will be the correct answer.
I'll let you try and work through question 19 on your own, but if you need help, let me know and I'll walk you through it!