Sufficient & Necessary Questions - - Question 27

Unless the residents of Glen Hills band together, the proposal to rezone that city will be approved. If it is the cit...

dgunderman March 20, 2020

When to count "probably" and similar words as part of a logic sequence

Why is "probably result in overcrowded schools" diagramed as a part of the logic sequence? My understanding was that statements that are in questions ("might"/"possibly"/"probably") could not be included in the logic chain, because we are not sure if it is or is not happening. Ultimately still came to the conclusion that "B" was the right answer, but now am unsure if I am identifying variables correctly in other problems. Thank you for your help!

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Ravi March 20, 2020

@dgunderman,

Great question. Here's how I'd diagram this stimulus:

residents don't band together-->proposal approved

proposal approved-->able to build water and sewer systems needed for apartments

apartments built-->population will increase

population increases-->new roads will be built

new roads or schools built-->substantial tax increases

Notice that I left the overcrowded schools part out of my diagram
because it's not certain. I would NOT diagram 'probably result in
overcrowded schools' in my diagram because this is not conditional
language.

Based on what we have in our diagrams, we should look for transitive
conclusions. Some of these statements do chain up.

The first two statements chain up to tell us that if residents do not
band together, then the city will be able to build the water and sewer
systems.

The rest of the premises in the stimulus combine to tell us that if
apartments are built, taxes will increase. These two chains must stay
separate because the water and sewer systems are necessary, but are
not sufficient, for apartments to be built.

(B) says, "If developers build apartment houses in Glen Hills, there
will be substantial tax increases for the residents of Glen Hills."

(B) looks great, as it's the conclusion that we got from the second
string of premises in the stimulus. If apartments are built, then we
know that there will be new residents who will require new roads,
which means there will be tax hikes. Thus, (B) is the correct answer
choice.

Hope this helps. Let us know if you have any other questions!