Critical Reasoning

An annually conducted, nationwide survey shows a continuing marked decline in the use of illegal drugs by high school seniors over the last three years.

Q. Which of the following, if true, would provide most support for concluding from the survey results described above that the use of illegal drugs by people below the age of 20 is declining?
(A) Changes in the level of drug use by high school seniors are seldom matched by changes in the level of drug use by other people below the age of 20.
(B) In the past, high school seniors were consistently the population group most likely to use illegal drugs and most likely to use them heavily.
(C) The percentage of high school seniors who use illegal drugs is consistently very similar to the percentage of all people below the age of 20 who use illegal drugs.
(D) The decline revealed by the surveys is the result of drug education programs specifically targeted at those below the age of 20.
(E) The number of those surveyed who admit to having sold illegal drugs has declined even faster than has the number who have used drugs.

OA is [spoiler](C)[/spoiler]. Why not [spoiler](B)[/spoiler]?

Thanks,
Rohit.

The question is asking to choose an answer choice which will provide most support to survey result so that it can be concluded that there is a decline in number of students below 20 years who take illegal drugs.

Survery result + supportive statement (answer choice) = conclusion (decline in number of students below 20 years who take illegal drugs )

Before looking at the answer choices, one possibility we can imagine that there is some impact on behavior of drugs usage on students below 20 years because of the behavior of drugs usage by seniors.

Now keeping this in mind, we can go through the answer choices one by one and choice C will fall in the above category. No other choice gives any convincing reason which can support both the facts.

survery result + answer choice C = conclusion.

This is what i can think. Any other takers please!!

Rohit, what is the soource of this question?

C: This looks ambiqous to me.
It could have 2 interpretations..

1) percentage of high school seniors inside the college is similar to
percentage of all people below the age of 20 who use illegal drugs
--Wrong (5% of high school seniors is defintely not equal to 5% of all people below the age of 20 who use illigal drugs)

2) percentage of all high school seniors is similar to
percentage of all people below the age of 20 who use illegal drugs
--correct...as the denominator for the percentage (all people below 20) is same for both


if i go by 1st meaning, B looks best
if i go by 2nd meaning, C looks best..why not B here? bcoz of the term "most likely"..well being good is certainly better than likely to be good .

vishwambhar wrote:The question is asking to choose an answer choice which will provide most support to survey result so that it can be concluded that there is a decline in number of students below 20 years who take illegal drugs.

Survery result + supportive statement (answer choice) = conclusion (decline in number of students below 20 years who take illegal drugs )

Before looking at the answer choices, one possibility we can imagine that there is some impact on behavior of drugs usage on students below 20 years because of the behavior of drugs usage by seniors.

Now keeping this in mind, we can go through the answer choices one by one and choice C will fall in the above category. No other choice gives any convincing reason which can support both the facts.

survery result + answer choice C = conclusion.

This is what i can think. Any other takers please!!

Agree, I took the same approach.

What is the source here?

I find that many books and various GMAT prep tests use questions which are not very similar to the real GMAT questions.

The first time I took the GMAT test, I found most questions to be very similar or almost identical to the ones in GMAT official prep books. Other sources often have questions which are too easy or too difficult and very misleading.

I don't see how C can be the correct answer here. The question is about high school seniors, so where did "all other people below the age of 20" get into the frame here? Shouldn't other people be irrelevant here or any such comparison out of scope?

Source: 1000 CR, Test 11, Q. 11

Thanks,
Rohit.

Hello Rohit,
While solving,I was also struck between B and C

How I eliminated B is as follows:

(B) In the past, high school seniors were consistently the population group most likely to use illegal drugs and most likely to use them heavily.

There is no reference regarding the Amount(heavily or lightly) in the question. Although, it's ok to Include information from Outside in Support/Weaken Question, but at the same time Scope has to be kept in Mind

I would go with option C