The program to control the entry of illegal drugs into the country was

Yes, you are right. If you use the assumption negation technique (ANT), you see that if the negative of option (E) is true, the conclusion cannot be true. Hence option (E) must be an assumption.
But let me add here that you should use ANT only when you get stuck or if you have doubts about the answer you have chosen. It is a little too complicated and time consuming to be used often.

The argument looks like this:
Premise: the wholesale price of most illegal drugs dropped substantially in 1987
Conclusion: the program was a failure i.e. the supply of illegal drugs did not drop.

Now, the argument looks shady, doesn't it? The price drop could happen because of increased supply or reduced demand. The author is concluding that the price drop is due to increase in supply (and says nothing about demand).

What is his assumption? His assumption is that the demand did not reduce or if it did, it did not reduce to the extent required to bring the price substantially down. So he is assuming that a reduction in demand was not the cause or at least was not the sole cause of reduction in the price.

Answer (E)
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While, generally, answering Critical Reasoning questions does not require the use of any sophisticated knowledge, understanding the logic of some Critical Reasoning questions requires a basic understanding of the economic laws of supply and demand. This question is such a question.

For anyone who is not familiar with the laws of supply and demand, here is a basic summary:

If the supply of a good increases and all other factors are held equal, normally the price of the good decreases. Conversely, if the supply of a good decreases, normally the price increases.

Demand affects price in the opposite way. If the demand for a good increases and all other factors are held equal, normally the price of the good increases. If demand decreases, normally the price decreases.

Now, let’s analyze the argument in this question.

The argument mentions a “program to control the entry of illegal drugs into the country.” This program is related to the laws of supply and demand in that the purpose of the program is to reduce the supply of illegal drugs in the country by controlling the entry of the drugs.

As discussed above, a reduction in supply should result in an increase in price, but the argument indicates that “the wholesale prices of most illegal drugs… dropped substantially.” In other words, even though there was a program meant to reduce supply, the prices fell.

Since one would expect that a reduction in supply would result in price increases rather than price decreases, the author of the argument reasons that since the prices decreased, supply must not have decreased, and therefore, the argument concludes, the program must have failed.

Now, let’s go to the answer choices to see which the author assumed in coming to that conclusion.

(A) The supply of illegal drugs dropped substantially in 1987.

Since the conclusion of the argument is that the program to reduce supply failed, this answer choice is not an assumption required for coming to that conclusion but rather is a statement in opposition to the conclusion.

(B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.

This answer choice is incorrect in two ways.

The first is that the author is not concerned with the prices consumers pay, i.e., the retail prices of illegal drugs. The author is concerned with wholesale prices of illegal drugs and has already made the case that supply did not drop by pointing to the drop in wholesale prices.

The second is that the conclusion states that the program to reduce supply failed. Any drop in prices of illegal drugs would be consistent with that conclusion. Therefore, clearly, the argument does not rely on the assumption that the retail prices of illegal drugs did not drop.

(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.

This answer choice could be tempting because an increase in domestic production of illegal drugs would result in an increase in supply, even if there were a program in place to reduce supply from foreign sources by controlling entry of drugs into the country.

So, this answer choice could explain why, even though there was a program to reduce supply, the prices of illegal drugs decreased; supply from domestic sources could have offset any reduction in supply achieved by the program to limit entry.

However, we are not looking for an explanation. We are looking for an assumption. So, this choice is not our answer.

(D) The wholesale price of a few illegal drugs increased substantially in 1987.

The conclusion of the argument is that a program to reduce supply failed. Since a reduction in supply would push prices upward, price increases would indicate that the program to reduce supply had not failed but instead had succeeded. So, the conclusion does not depend on assuming that any prices of illegal drugs increased.

(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.

Correct. The argument’s conclusion, that the program to reduce supply failed, is based on the fact that the prices of illegal drugs dropped. In arriving at its conclusion, the argument relies on the assumption that there was not some other reason for the decreases in the prices of illegal drugs. Therefore, that a drop in demand was not the sole cause of the price drop is an assumption upon which the argument depends.

The correct answer is E.
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The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

Here author is considering the program failure is the only cause for drop in prices.
13. The argument in the passage depends on which of the following assumptions?

(A) The supply of illegal drugs dropped substantially in 1987.
(B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.
(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.
(D) The wholesale price of a few illegal drugs increased substantially in 1987.
(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.
( If failure of the program is the only cause for drop in prices then it is surely preassumed that " A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price." )

Let me just try -

1) The program to control the entry of illegal drugs into the country was a failure in 1987 - The program was a failure

2) If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

Thus, it means that the program was not successful ( there was illegal entry of drugs into the country) and hence, the prices dropped.

If I negate E - A drop in demand for most illegal drugs in 1987 was THE sole cause of the drop in their wholesale price.

okay - so if the price decrease was due to the drop in demand; the illegal entry of drugs was not the reason of their wholesale price decrease.

Am I right ?

E is correct. If you negate E, which becomes "Drop in demand WAS the sole cause of drop of wholesale price", the argument explodes into smithereens.
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The only choice that must be true in order to conclude legitimately from the drop in wholesale price of illegal drugs that the program was a failure is choice E, the best answer. If the drop in price was caused by a drop in demand, there is no reason to suspect that there has been any increase in supply caused by drugs entering the country.

The other choices can be false without affecting the argument. The supply of illegal drugs need not have dropped (choice A), and the retail price could have dropped (choice B). The entry of illegal drugs could have risen at a higher rate than domestic production (choice C), and no illegal drug need have undergone a substantial price rise (choice D).

The conclusion in this argument is that the program to control the entry of illegal drugs into the country was a failure.
The argument used evidence that if the program had been successful, then the wholesale prices of illegal drugs would not have dropped substantially.
So, the argument assumes that change in the wholesale price of drugs is related to the success or failure of the program. there is no other reason for the drop in prices.


this statement tells us that only the supply dropped. no information about demand. if demand increased and supply dropped, then the prices should rise.
if demand also decreased then what. eliminated.


if the price did not increase then it is related to sales. it means that the sales were constant. irrelevant. eliminated


domestic production increased it means that it shows another cause that because of local production, there was a decrease in prices. but we need to make sure that there is no other cause. eliminated.


A FEW is a small number. if the wholesale price of a few increased that means the program would have been a success. but still if out of 1000 drugs, prices of 2 drugs increased then it does not lead to the conclusion. eliminated.


this option tells us that the drop in demand was not the SOLE cause in the drop in prices. it means that there was some other cause. that cause was the failure of the program. correct.

The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

Program to control the entry of illegal drugs -> failure
Program successful -> no drop in price
Drop in price -> Program unsuccessful

The reasoning is actually well connected. I don't find any missing link here. So this should be a defender assumption question type. We must defend that the failure of the program was the reason that caused price drop. Any answer choices that refute this will be wrong.

The argument in the passage depends on which of the following assumptions?



This, if anything, weakens the argument. It is saying that the program actually successful and that something else must have caused price drop. (A) is out.

What the price actually was is irrelevant. What moved the price was the central point. (B) is out.

So this is saying that the increase in supply caused the price movement, which is already mentioned in the premise. This does not advance the argument. (C) is out.

This is again similar to B. (D) is out.

This matches our thought, removing the possible case that the eliminate the program as the cause of the price drop. Hence (E) is the correct answer.
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Hi VeritasKarishma

I chose 'E', however, I was a little skeptical about the verbiage. Don't you think the usage "...was not the solecause of the drop..." is extreme ? I mean, author doesn't have to assume that demand was not the "sole" cause of the drop. It could have been one of the 2 causes, Right ?
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Option (E) makes sense because it uses the word "sole". I don't know why many test takers think in terms of "the option is extreme" but it is not valid. There are no extreme options. In some cases, words such as "all", "none" etc are justified and in others, they are not - just like any other word. You need to see whether it is justified in the case presented to you.

When the author says that price drop in 1987 implies that supplies continued at a healthy level or even increased, he is assuming that the reason for the price drop is related to the supply side. This means he is assuming that fall in demand is not the sole reason.
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OFFICIAL GMAT EXPLANATION

The only choice that must be true in order to conclude legitimately from the drop in wholesale price of illegal drugs that the program was a failure is choice E, the best answer. If the drop in price was caused by a drop in demand, there is no reason to suspect that there has been any increase in supply caused by drugs entering the country.

The other choices can be false without affecting the argument. The supply of illegal drugs need not have dropped (choice A), and the retail price could have dropped (choice B). The entry of illegal drugs could have risen at a higher rate than domestic production (choice C), and no illegal drug need have undergone a substantial price rise (choice D).

The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

The argument in the passage depends on which of the following assumptions?


(A) The supply of illegal drugs dropped substantially in 1987.

(B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.

(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.

(D) The wholesale price of a few illegal drugs increased substantially in 1987.

(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.


The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.


the program failed so illegal drugs increased in supply. By saying that the prices would not have dropped if the program had been successful, the argument assumes that increased supply was the reason that decreased the price and does not consider other reasons that could have decreased the price regardless whether the program had or had not been implemented.

usually when they talk about price, supply, and demand, you can prethink the answer.
there are two ways prices can decrease when considering supply and demand.
if supply increases, prices decrease
if demand decreases, prices decrease

clearly the argument did not consider the following option:
if demand decreases, prices decrease

(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.

The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

Conclusion: the wholesale price of most illegal drugs would not have dropped substantially in 1987. " If amount of drugs coming into the country increases, this means a supply increase in drugs, and will result in a lower price for it. supply vs demand.

The argument in the passage depends on which of the following assumptions?


(A) The supply of illegal drugs dropped substantially in 1987.wrong. supply should increase.

(B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.the price paid is not an assumption that is needed.

(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.we are talking about drugs entering the country, not domestic production.

(D) The wholesale price of a few illegal drugs increased substantially in 1987.price should have decreased.

(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price. if a drop in demand WAS the sole cause of the drop, the argument fails. This is the right answer.

Hello experts,

C'. Domestic production of illegal drugs DID NOT increase at a higher rate than did the entry of such drugs into the country.

Can this be an assumption too?

VeritasKarishma ScottTargetTestPrep AndrewN

Hello, ashmit99. You have to read the question stem carefully to avoid associative reasoning that can lead you wayward. We are not interested in assumptions that could be made, but in the one assumption of the options provided that the argument depends on. In other words, if such an answer were untrue, then the argument as presented would collapse. I would hope that the earlier responses in the thread help clear any doubts about (C), but if you still have questions, let me know.

- Andrew
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Thanks for replying AndrewN

Got your point. But if I negate C' it would become the original option C.

So C says that domestic production increased at higher rate than did entry of such drugs into the country.

So basically now it seems like even if the program had been successful, the wholesale price still would have dropped substantially.

So in this case, the conclusion breaks.

Please help me with my doubt.

Thanks!

Hello again, ashmit99. I did not say anything about negation exactly. Your goal is simply to find the one answer choice that necessarily bridges the gap between premise and conclusion. I use a drag-and-drop (or missing link) strategy instead of the negation technique when taking on such questions. Test (C) as is between the premise and conclusion:

Premise: If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.

Conclusion: The program to control the entry of illegal drugs into the country was a failure in 1987.

Analysis: Why are we focused on a rate of growth between the domestic production of drugs and the importation of drugs? Whether the domestic production outpaced the importation is beside the point. The conclusion about the program to control the entry of illegal drugs into the country could hold, regardless of what may be going on with domestic production. Answer choice (C) cannot be our necessary assumption.

Repeat the process for (E):

Premise: If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.

Conclusion: The program to control the entry of illegal drugs into the country was a failure in 1987.

Now this makes more sense. As evidence of the assertion, the argument points to the wholesale price of most illegal drugs. Choice (E) touches directly on this concern and informs us that demand for such drugs was not the sole cause of the drop in wholesale price, so there must have been other factors at work. Perhaps, then, the conclusion can be made that the program was a failure. At least the connection is clear, and that is all we are looking for in this sort of question.

I hope that makes more sense.

- Andrew
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An option would need to be worded very carefully to make it an assumption.

Other than option (E), an assumption is: "Dramatic increase in domestic production was not the sole cause of price drop."

Rate of increase in domestic production vs rate of increase in illegal import doesn't make much sense.
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Hi AndrewN

I was confused between B and E and chose B. My reason was-
If the average customer refused to pay high price for illegal drugs, the wholesale price of the commodity would have to be dropped. Where did I faulter in my reasoning here.