Q13 - Mayor: To keep our neighborhoods clean

[mshinners]

Question Type:
Inference (Must Be True)

Stimulus Breakdown:
Mayor's Cleanliness plan:
1) Every street swept 1+ per month
2) If more are needed, street qualifies for interim cleanings
3) All interim requests from qualified streets will happen immediately

Answer Anticipation:
There's overlap between the second and third statements. If a street needs more frequent cleanings, all requests it makes will result in an immediate cleaning. I guess they have some street cleaners sitting by the phone, waiting anxiously for a call.

Correct answer:
(D)

Answer choice analysis:
(A) Major construction is given as an example of something that could lead to a street qualifying for extra sweepings. However, this answer is about all construction, and the stimulus gives major construction as an example, so this answer isn't supported. If a street is undergoing minor construction, it would be undergoing construction (so this answer would apply), but the stimulus doesn't guarantee they qualify.

(B) Tempting, but the street only gets an extra cleaning if they request one. A qualified street that never requests an additional cleaning would only receive one cleaning a month.

(C) Illegal reversal. The stimulus establishes that a qualified street can receive a second sweeping, but it never states that it is the only kind of street that will receive extra cleanings. Maybe, for example, all streets are cleaned after a major storm.

(D) Bingo. Qualified neighborhoods can request a cleaning to happen immediately. Since this answer specifies that it requested an interim cleaning (not a regular one) and that these cleanings happen immediately, that street will receive more than once sweeping that month.

(E) Illegal negation. While the rules established don't guarantee a non-qualified street's request from being honored, they also don't prevent it. If it's a slow week, it's possible the sweepers would honor this request.

Takeaway/Pattern:
Look for overlap, and don't be afraid to clearly lay out the rules.

#officialexplanation

[cacrv]

Can someone diagram why C is wrong?
I get that C is wrong because there might be more ways than being in a qualified neighborhood to justify an extra sweeping, but I'd like to confirm my diagramming for this question - thanks in advance!

[ohthatpatrick]

No prob. We should have a complete explanation up here.

Question: Inference

Task:
Read the facts. Synthesize any Conditional, Causal, Quantitative ideas you find. Pick any answer choice you can prove from the available facts.

The Facts:
Keeping the 'hood clean ---requires---> street-sweeping at least once / month

A 'hood needs more than once/month -> qualifies for interim sweepings

Request for interim sweeping from qualified neighborhood -> prompt sweeping

Can We Synthesize Any of This?

There aren't any direct symbol-to-symbol links, but there's definitely some overlapping ideas.

Basically, if you live in this city, you're gonna get at least one street cleaning per month. But say you just had your cleaning for this month and then you get a bunch of dirt dumped on your street from some construction project -- in that case, rather than wait until NEXT month's street sweeping, your neighborhood qualifies for an "interim" sweeping (i.e. SOONER than next month), and the city will come by and provide that interim sweeping very swiftly.

Let's check out some answers.

(A) All 'hoods with construction are qualified neighborhoods? I don't feel good about committing to that. We only heard, as one POSSIBLE example, that MAJOR construction projects MAY create a need for more frequent sweepings.

(B) Hmm, seems like All Qualified would get more than one sweeping per month. If you're already having a minimum of one per month and then you get an EXTRA sweeping, then that's more than once a month. How would this fail to happen? Well .. the rule that ACTUALLY gets your street the extra sweeping is the last sentence. A "request" for an interim sweeping gets an extra sweeping. Do I really know that ALL Qualified neighborhoods will submit requests for the extra cleaning? Maybe not.

(C) There's no way to prove that something WON'T get swept. The mayor could easily decide to give any neighborhood an extra sweeping whenever she so chooses.
Symbolically,
IF a street gets swept more than once, THEN it's qualified neighborhood.

The closest thing we know is
IF qualified neighborhood, THEN a street COULD get swept more than once

(D) Oh, sweet. This is like (B), only THIS one guarantees that a qualified neighborhood requested a sweeping. When qualified neighborhoods ask, this mayor delivers an extra sweeping IMMEDIATELY. And "extra" + "one guaranteed sweeping / month" = "more than once a month".

(E) This is like (C). There's no way to prove you WON'T get extra sweepings. The mayor's rules only stipulate what guarantees you WILL get an extra sweeping. She could easily drive around giving unqualified neighborhoods extra sweepings without violating any of her stated rules.

Hope this helps.

[smsotolongo]

The stimulus says that all streets are swept "at least once a month." Using this I eliminated choice B. A neighborhood may get its streets swept more than once a month and it's not qualified. Am I off?

[contropositive]

I eliminated C and E because they both spoke of unqualified neighborhoods, but the author does not talk about unqualified neighborhoods. it seems like he is saying the neighborhood in the city are all qualified. Am I wrong?

Also, I noticed sometimes arguments provide an example and then there is an answer choice that talks about the example...just like A in this argument. This happens on variety of question types and it's never been the right answer. Should I just eliminate answers that speak of the example unless the example is the foundation of the argument?

[ohthatpatrick]

To the previous poster (two back), it sounded like you were asking,
"Can we get rid of B, because unqualified neighborhoods might ALSO get their streets swept more than once a month?"

If that was your question, the answer is no. Saying that "all qualified get more than one" doesn't mean "no unqualified get more than one".

I could say
"All male citizens deserve basic human respect."
That doesn't mean that I suddenly believe "no female citizen deserves basic human respect."

To the last poster, you're basically correct about eliminating (C) and (E) because it's about "unqualified". It's not fair to say we know nothing about them. Given the conditional the author gave us about 'qualified neighborhoods', we get the contrapositive:
"If your neighborhood is UNQUALIFIED for interim sweepings, then your neighborhood doesn't really need more frequent sweepings than the normal once a month minimum."

That's ALL we know about unqualified neighborhoods. So we can't comment on what (C) and (E) say about all unqualified neighborhoods.

In terms of the "due to construction, for example" thought ... you're very correct to sense that whenever they introduce specific examples that aren't the core concepts supporting the conclusion (just an illustration of the more general idea), then they aren't important to go back to in any way. They're just there so that LSAT can fill up some trap answers with familiar sounding words.

For (A), you just need to ask yourself, "Can I prove this?"

Did the information provide a universal truth about ALL neighborhoods-with-construction?