must be true question

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must be true question

by hey_thr67 » Mon Jun 25, 2012 11:23 am
A recent research study of undergraduate students analyzed the effects of music on human emotions. Each of the 200 participants attended at least 1 two-hour concert of classical music per week over the course of 12 weeks of their spring semester. At the end of the experiment, all of the students filled out a questionnaire assessing their emotional state. Based on the results of the questionnaires, all of the 10 students who attended the greatest number of concerts reported lower stress levels and higher satisfaction with their lives. Also, most of the 20 students who attended the fewest number of concerts reported below-average levels of emotional comfort.

Which of the following must be true based on the evidence presented above?


A: Most of the 200 participants improved their emotional state and lowered their stress levels.

B: During each week of the experiment, the participants spent at least 2 hours less on their academic work as a result of concert attendance.

C: Listening to classical music for at least 2 hours per week improves the emotional well-being of the majority of young adults.

D: More than 6 participants attended at least 14 concerts during the course of the experiment.

E: At least some of the students participated in the study in order to gain free access to classical concerts

OA is D
Source: — Critical Reasoning |

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by Kasia@EconomistGMAT » Mon Jun 25, 2012 12:49 pm
Answer A is out of scope since we don't know how many more participants reported worse emotional state
Answer B is also out of scope - this information is not given
Answer C is very attractive but it is a distractor
Answer E is out of scope since we are not told what the students' motivations were
Answer d is correct although it looks too complicated to be the right choice
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by saviogmat » Mon Jun 25, 2012 9:56 pm
Kasia@MasterGMAT wrote:Answer A is out of scope since we don't know how many more participants reported worse emotional state
Answer B is also out of scope - this information is not given
Answer C is very attractive but it is a distractor
Answer E is out of scope since we are not told what the students' motivations were
Answer d is correct although it looks too complicated to be the right choice
Hi Kasia,

Can you explain how D could logically be the right choice? The stem states that the 10 students who attended the greatest number of concerts. Based on this, one way could also be that just 1 student attended 6 nos of 2 hour concerts, 2 attended 7 nos and the balance 7 students among the top 10 attended just 5 weeks of 2 hour concerts. These could be the best attendance in the group of 200. Please advise

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by Chandra Gurrum » Tue Jun 26, 2012 12:11 am
It is mentioned that "Each of the 200 participants attended at least 1 two-hour concert of classical music per week over the course of 12 weeks of their spring semester". This means that minimum number of concerts one can attend is 12concerts.
So, there are 20 students who attended 12 concerts.

Remaining number of students are 200-20=180;

Also it is mentioned that "all of the 10 students who attended the greatest number of concerts". Subtracting this 10, the remaining number of students are 170.

So, 170 students must have attended greater than 12 concerts. So consider the least number greater than 12 which is 13.

So, if we consider 170 students attended 13 concerts, then the possible least maximum number of concerts 10 students attended must be 14 concerts.

So, the option "More than 6 participants attended at least 14 concerts during the course of the experiment." is true.