#23 - Each new car in the lot at Rollway Motors costs more

[Administrator]

Please post your questions below! Thank you!

[samsamsam]

Why not D?

I chose B, but I think it's wrong because of the "two or three bedrooms." The answer choices are very hard to understand.

[James Finch]

Hi Sam,

This is a parallel reasoning question, so the correct answer choice will include the exact same reasoning as the stimulus, meaning we have to know the stimulus's reasoning first. In the stimulus we have two conditionals:

New >18k

and

10-yrs-old <5K

Then the stimulus puts together the contrapositives and comes up with:

>18k and <5K New and 10-yrs-old

This is exactly what our correct answer will do.

(B) gives us:

>4 2BR or 3BR

and

<4 2BR or less (aka 3BR)

and then concludes

3BR <4

Which only uses the contrapositive of the second conditional for the conclusion, not combining the two conditionals as in the stimulus.

(D) gives us:

>4 >2BR

and

B 3BR

and concludes

B 3BR >4

Which is taking the contrapositive of the first conditional and chaining it onto the second to create an inference. Solid reasoning, but not what we have in the stimulus.

Ultimately, only (C) works, as it gives us:

>4 min 3BR

and

<4 <2BR

And concludes by taking the contrapositives and combining them, just like in the stimulus:

min 3BR and <2BR >4 and <4 4

Hope this clears things up!

[ShannonOh22]

Hi guys,

I went with E on this question, which is wrong, but I'm having trouble figuring out the diagramming so I can trace where I went off track. Can you please let me know where I'm off base in the below?

Stimulus:
new car --> >$18k
10+yrs old --> <$5k

Conclusion: >$18k+ and <$5k --> new car and 10+yrs old

E):
above 4th floor --> >2 BR
4th floor and below --> vacant apts

Conclusion:
vacant apts and 4th floor and below --> >2 BR and above 4th floor

I've just sufficiently confused myself...please help!

[Paul Marsh]

Hi Shannon! Your diagram of the stimulus is right on the money.

But answer choice (E) would be diagrammed as follows:

Premise 1: Above 4th floor > 2 bedrooms
Premise 2: Above 4th floor Vacant (and the contrapositive would be Vacant Above 4th Floor)
Conclusion: Vacant >2 bedrooms

That conclusion follows correctly, since the contrapositive of Premise 2 chains together with Premise 1 to reach the conclusion. However, although it is a logically sound argument, it is not the correct answer choice because the diagram is different than that of our stimulus in important ways. For example, the sufficient conditions of our first and second premises are logical opposites (negations) of each other. This was not the case in our stimulus.

Answer choice (C) however, matches our stimulus diagram perfectly:

Above 4th floor 3 or more bedrooms
Below 4th floor Fewer than 2 bedrooms
3 or more bedrooms and Fewer than 2 bedrooms Above 4th Floor and Below 4th Floor

Hope that helps!

[ange.li6778]

Hi powerscore, do yall have any advice on trying to do this question quickly or do we just have to diagram each conditional and contrapositive in the answer choices? For example, are there answers that can be quickly ruled out after an initial skim? TIA!

[Adam Tyson]

When I am faced with multiple conditional claims in the stimulus, ange.li6778, I always diagram them, and for me that is the fastest, best approach, even if it feels a little slower than I might like.

But once we get to the answer choices, since this is a Parallel Reasoning question, there are some things we can do to shorten the time spent on them. Before diagramming any answer choices, see if they have a fatal problem that takes them out of the running. For example, answer B's conclusion introduces an alternative - "or higher" - while the stimulus had a completely certain conclusion with only one choice. Answer D has the same problem when it gives the alternative of "or lower." And answer E is a "more than" answer, when our stimulus is about "if a car is in this group, it must have this characteristic." Those sorts of mismatches in the strength and type of language are enough to reject them, leaving us with only two answers worth considering. When that's the case, you only need to diagram one answer! Either it matches the stimulus, in which case you should select it, or it does not match, in which case you should just select the only remaining contender, confident that the other answers are all losers.

Don't start by diagramming answers! Start by sorting them out into those that are worth a second look and those that are not, and THEN decide if a diagram is needed to determine the winner.