#25 - The more demand there is for something, the easier it

[Administrator]

Please post your questions below!

[chian9010]

Dear Powerscore,

I have questions on A and E. Could you tell me why A is wrong?
Thank you,

[James Finch]

Hi Chian,

The issue with this question is that we're dealing with broad ideas in the first and last sentences (the latter being the conclusion to the stimulus) in which More Demand Easier to Sell. But the other premises concern only junkyards interested in parting out old vehicles and selling those parts, not selling cars as a whole. So while we have good information about the demand for parts of cars, we don't have information about demand for those cars overall. We have to tie those two things together (with an assumption) in order to allow the conclusion to be true.

(A) would work if it was talking about "demand for [parts] of it"--demand for old car parts being a known quantity--and not overall demand for the thing itself (we don't know what the demand is for old cars as a whole). (E) works because it ties the demand for the parts of the old cars to demand for the old cars as a whole, allowing us to draw the conclusion about old cars as a whole based only on knowledge about the demand for their parts.

Hope this clears things up!

[t_m6289]

Could someone let me know if this is an appropriate way to rule out B, which I originally selected?

At first I thought that B was necessary since the argument only talks about the demand for used cars in junkyards. If there is demand for the older cars coming from somewhere other than junkyards, then the author wouldn't be able to conclude that the newer used cars are easier to sell than the older used cars.

But on review I noticed the use of "generally" in the conclusion, which leaves open the possibility that the older used cars are sometimes easier to sell than the new used cars. If that's the case, then the demand for the newer used cars doesn't have to be universally higher than demand for the older used cars, meaning that B isn't actually necessary.

Is that a reasonable way to rule out B?

[Zach Foreman]

t_m,
You are on the right track. I would use the assumption negation technique. Remember that if we negate the assumption, that should torpedo the conclusion. So, what if "Not all used cars that are ten years old or older are sold to junkyards." Well, the conclusion could still be true, since, if 80% of used cars are sold to junk yards, the conclusion could still be true.
But let's negate the correct answer. "The salability of cars that are ten years old or older is NOT largely a function of the level of demand for their parts." This directly contradicts the first sentence, a premise. If salability is NOT a function of demand in this instance then we can say nothing about used cars salability, either older or newer than ten years. So, this time the negated assumption negates the conclusion so it is the right answer.

[t_m6289]

Thanks, Zach, that makes sense!

[Sambenz]

t_m,
You are on the right track. I would use the assumption negation technique.

From what I understand, I don't think the assumption negation technique works here because this is not an assumption question, but a justify the conclusion question. With JTC questions, the difficult part is identifying the missing premise so negating doesn't help identify the missing link. With assumption questions, you're looking for the implicit assumption, so it is more difficult to tell which assumption truly matters, and so negating is more helpful there. That's at least how I understand it.

I originally misread the stimulus, which I found very tricky. It is easy to confuse the supply and demand for the parts and the supply and demand for the cars themselves. When I read the conclusion, I didn't catch that it was referring to the entire car, so when I looked through the answers none really appealed. I chose D, but I was quite unsure. Looking back I think I just needed to read more closely.

[Adam Tyson]

This one is actually an Assumption question, Sambenz, and not a Justify the Conclusion question, and that is why the Assumption Negation Technique will work here. Here are a few ways to tell which type this is:

1. The stem does not say "if true" or some equivalent phrase. Justify questions almost always use that language of sufficiency.

2. The stem says the argument depends on the answer - that means the correct answer is necessary, rather than the correct answer being sufficient.

3. The stem does not say anything about the conclusion being properly drawn, or following logically, or justifying the conclusion, etc. Justify stems have language that indicates that when the correct answer is added to the argument, the conclusion will be proven or required.

"Which of the following is an assumption..." is an Assumption stem, and the Negation Technique can be used to test your contenders. The answer that, when negated, invalidates the argument will be the right answer, and the ones that do not invalidate it when negated are wrong answers. Give it a try here and see how it works out for you!

[appletree]

Hello!
Could someone show the negation of C and why it is not the correct choice? Thank you!

[Rachael Wilkenfeld]

Sure thing appletree.

The negation of answer choice (C) would be something like "In general, being older does not make something more difficult to sell."

This does not hurt the argument, because we aren't making a point about items in general, it's a specific argument about a specific item. There's also a bright line at 10 years, and not a general rule that we can apply to one year old v two year old cars, for example. We don't need it to be true that generally older things are more difficult to sell.

Hope that helps!