To become an expert on a musical instrument, a person must practice. I

Question

To become an expert on a musical instrument, a person must practice. If people practice a musical instrument for three hours each day, they will eventually become experts on that instrument. Therefore, if a person is an expert on a musical instrument, that person must have practiced for at least three hours each day.

Which one of the following most accurately describes a flaw in the reasoning above?

(A) The conclusion fails to take into account that people who practice for three hours every day might not yet have reached a degree of proficiency that everyone would consider expert.

(B) The conclusion fails to take into account that practicing for less than three hours each day may be enough for some people to become experts.

(C) The conclusion fails to take into account that if a person has not practiced for at least three hours a day, the person has not become an expert.

(D) The conclusion fails to take into account that three consecutive hours of daily practice is not recommended by all music teachers.

(E) The conclusion fails to take into account that few people have the spare time necessary to devote three hours daily to practice.

GMATNinja · Accepted Answer

The author's conclusion is that "if a person is an expert on a musical instrument, that person must have practiced for at least three hours each day." Let's examine the logical flow...

"To become an expert on a musical instrument, a person must practice." - This statement gives a  necessary  condition. If you want to become an expert on a musical instrument, you MUST practice. 
 "If people practice a musical instrument for three hours each day, they will eventually become experts on that instrument." - This statement gives us a  sufficient  condition. If you want to become an expert on a musical instrument, practicing for three hours a day WILL allow you to achieve that goal. However, this is not necessarily the ONLY way to achieve that goal. For example, you might just be a gifted musical genius who can play the piano at an expert level with very little practice! 
 Therefore, the conclusion is flawed. Although practicing for three hours a day is one way to become an expert, it is not necessarily the only way (it is sufficient but not necessary). Choice (B) describes this flaw in the reasoning.

I hope that helps!

rohitkabra1987 · Answer

Although i selected B which matches the OA , i am not clear about the logical flow to arrive at the correct option .Can the experts please pitch in ? Thank you !

rocky620 · Answer

Hi GMATNinja, Option C also provides the same reasoning as does Option B.
Can you help and elaborate?

devavrat · Answer

Confused between option A and option B 
What makes option B stronger than option A

chaitralirr · Answer

To become an expert on a musical instrument, a person must practice. If people practice a musical instrument for three hours each day, they will eventually become experts on that instrument. Therefore, if a person is an expert on a musical instrument, that person must have practiced  for at least three hours each day .

Which one of the following most accurately describes a flaw in the reasoning above?

(A) The conclusion fails to take into account that people who practice for three hours every day might not yet have reached a degree of proficiency that   everyone would consider expert  . The underlined part makes the option B better than A

(B) The conclusion fails to take into account that practicing for less than three hours each day may be enough for some people to become experts.

Stimulus states: To become an expert in music one must practice and if one practices music for 3 hours a day he/she will become an expert in music. Therefore if a person is an music expert he or she may have practiced music for  atleast  3 hours for a day. The word at least is the clue here.

sharathnair14 · Answer

I've got one question about flaws. Maybe I lack some conceptual knowledge about Find the flaw questions, but nevertheless -
Don't Flaws in an Argument need to be internal? And doesn't a flaw only have to consider the given information? 
Isn't assuming some musicians as gifted (which makes sense and probably is an obvious fact) external information?

GMATNinja · Answer

Take another look at the conclusion of the passage:
 
The first piece of that sentence ("if a person is an expert on a musical instrument")  places a condition  on the conclusion. In other words, it  limits the application  of the second part of the sentence ("that person must have practiced for at least three hours each day"). So, the author is ONLY making an argument about people who are experts on musical instruments -- he/she has deliberately excluded any "non-experts" from the equation.

To assess the reasoning of the argument, we really only care about the actual argument that the author has made. What flaw does he/she make in drawing his/her  exact  conclusion from the evidence cited in the passage?

Here's (C):
 
This answer choice does not address the argument actually made in the passage -- the author concludes that experts must have practiced for at least three hours each day. The fact provided in (C) may (or may not) be true, but because (C) makes a statement about a completely different group of people (non-experts), it cannot be a flaw in the reasoning of the passage as it is written. Eliminate (C).

(A) can be eliminated for a reason similar to that we used to eliminate (C) above.
 
The author limits his/her conclusion to apply only to people who are  already  experts. Let's say that Joe picks up a bassoon practices for three hours each day for three days. After just a few days of practice, Joe is probably not an expert. So, it is entirely possible that "people who practice for three hours every day might not yet have reached a degree of proficiency that everyone would consider expert"!

However, can we say that the conclusion  fails to take this into account?  No, we can't -- the conclusion  only  applies to those already considered experts, so the fact that Joe is not yet considered an expert is not a flaw in the reasoning of the passage.

Contrast that with (B):
 
The author argues that if a person is an expert, that person MUST have practiced for at least three hours each day. In other words, there is only ONE path to expertise -- practicing at least three hours each day.

This conclusion is based on the evidence that if a person practices for three hours each day, that person will become an expert. Notice that this is only one POTENTIAL way that a person will become an expert, which leaves open the possibility of other paths to expertise. Maybe you're just a musical genius, or maybe you can sell your soul to the devil and become an expert fiddler after just an hour of practice.

The flaw in the reasoning of the passage is that the conclusion  fails to account  for these other ways to reach an expert level. By saying that all experts MUST have practiced for at least three hours a day, it (without justification) turns the  potential  path to expertise cited into the passage into the  only  path to expertise.

(B) is the correct answer.

I hope that helps!

VerbalBot · Answer

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