What does the Question Stem tell us?
Sufficient Assumption
Break down the Stimulus:
Conclusion: Sticking with current platform will allow W to win the election.
Evidence: If she sticks with current platform, she'll comfortably win the 50 and over demographic, while barely losing the under 50 demographic.
Any prephrase?
This is very straightforward, since both the conclusion and premise use the idea of "sticking with her current platform". We just need to get from "win the 50 and over, lose the under 50" to "win the election". It seems like we just need to know that there will be more votes coming from the voting bloc where she wins, fewer votes coming from the voting bloc where she loses.
Correct answer:
D
Answer choice analysis:
A) We only care about the effects of sticking with the current platform. This has nothing to do with the relative quantity of over 50 vs. under 50 voters.
B) We don't care about the difference in "issues" between these two voting groups, just their relative size. This may feel like a NECESSARY assumption, but it certainly doesn't PROVE to us that winning the over 50 group = winning the election.
C) We only care about sticking with current platform, and only need to know about the size of the voting groups.
D) Here we go! If she wins the bigger group of voters by a bigger margin than she loses the smaller group of voters, then she'll definitely have more votes! (Now we just have to assume that more votes = win the election, which is true in LSAT's commonsense universe, even though it isn't true in the U.S's ridiculous electoral system ... /rant)
E) Oh my goodness why are we still talking about changing the platform?
Takeaway/Pattern: This had a very simple structure.
Premise: If A then B.
Conclusion: A would lead to C.
The gap: B would lead to C.
Once we know we have to get from "win the over 50 crowd" to "win the election", D becomes the only choice that would do that work.
#officialexplanation