Most people who are skilled banjo players are also skilled guitar

Question

Most people who are skilled banjo players are also skilled guitar players. But most people who are skilled guitar players are not skilled banjo players.

If the statements above are true, which one of the following must also be true?

(A) There are more people who are skilled at playing both the guitar and the banjo than there are people who are skilled at playing only one of the two instruments.

(B) A person trying to learn how to play the guitar is more likely to succeed in doing so than is a person trying to learn how to play the banjo.

(C) Playing the guitar takes more skill than playing the banjo does.

(D) There are more people who are skilled at playing the guitar than there are people who are skilled at playing the banjo.

(E) There are more people who are skilled at playing the banjo than there are people who are skilled at playing the guitar.

eabhgoy · Answer

Let us break down the passage:
Most people who are skilled banjo players are also skilled guitar players. 
So if we consider there are 10 people who can play the banjo then these 10 people can also play the guitar.

But most people who are skilled guitar players are not skilled banjo players.
From this statement, we can see that very few guitar players know how to play the banjo. So if we had (10 guitar players + banjo players), this is a very small % of people who play the guitar. So we can say that 1000 people play the guitar and out of which only 10 play banjo which is a small %.

Hence we can see that the number of guitar players > the number of banjo players.

Hence D is the correct answer.

mykrasovski · Answer

Dear experts, is it possible to see a similar question on a GMAT? Also, how do you dissect the question of this type?

I only managed to understand the logics by using Venn diagrams.

alexx2 · Answer

Can anybody explain why B is wrong?

Montyyy95 · Answer

GMATNinja  do we solve LSAT CR questions to prepare for GMAT ?
And if possible could you give an explanation for this question?

Posted from my mobile device

GMATNinja · Answer

Using LSAT questions to prep for the GMAT is definitely worth considering, as I've explained in  this blog post .

This particular question is a good example of a question that's more difficult than you'd expect to see on the GMAT, but let's go ahead and unpack what the passage is telling us:

Ouch! This is a brain-hurting scenario for sure, so it'll help to use simple numbers to create a logical sketch of this scenario.

Let's say that there are 100 skilled guitar players. "Most" of them are NOT skilled banjo players, so we'll say for the sake of illustration that among these 100 skilled guitar players, 20% of them are skilled banjo players and 80% of them are NOT skilled banjo players.

So far, we've got:

80 players skilled at guitar 
  20 players skilled at guitar + banjo

We also know that  most skilled banjo players are  also  skilled guitar players . And in this scenario, we've already identified 20 skilled banjo players who are  also  skilled guitar players. So in our sketch, the 20 players who are skilled at both instruments must represent most (i.e., 80%) of all skilled banjo players.

Consequently, we shouldn't expect to find more than 5 skilled banjo players in addition to these 20. Now we've got:

80 players skilled at guitar 
  20 players skilled at guitar + banjo 
  5 players skilled at banjo

Now, the 80% figure we've assigned to "most" is arbitrary. But it illustrates the logical meaning of "most." We can change this number to 70%, or 60%, or even 51% to illustrate these groups — and we'd end up with the same logical observation: There are more skilled guitar players than skilled banjo players in this scenario.

This matches answer choice (D):

Now, let's double check each other answer choice.

Nope! Given the proportions that this passage has provided, there's no way this can also be true. Eliminate (A).

A person trying to learn how to play the guitar is more likely to succeed in doing so than is a person trying to learn how to play the banjo. 
The passage doesn't give us any information about people  trying to learn  guitar or banjo. It only tells us about people who are  already  skilled at one or both of these instruments. Because we have no idea how many people tried to learn guitar or banjo, we can't infer anything about how likely they were to succeed at learning that skill.

Perhaps a ton of people tried learning the guitar and failed before they became "skilled players"... or perhaps the opposite is true, and many people tried to learn the guitar and did not succeed in that endeavor.

We can't infer how likely people were to succeed in learning either instrument, so eliminate (B).

There is no information in the passage to support this statement. We don't know  why  the distribution of skilled banjo and guitar players turned out this way... and if anything, the passage makes it seem like playing the  banjo  takes more skill than playing the guitar. Eliminate (C).

As with choice (A), a quick look at our sketch shows that this can't possibly be true. Eliminate (D).

(D) stands as the only answer supported by the passage. I hope this helps!

RahulJain293 · Answer

I answered this using the methods shown in the Youtube video here:

https://www.youtube.com/watch?v=nXwhwU_yIFE

btsaami · Answer

The stimulus states that most of skilled banjo players are also skilled guitar player but most skilled guitar players are not skilled banjo players. So from this we can infer that, majority of skilled guitar player will be greater than the minority of skilled guitar player who are also majority of skilled banjo player i.e. Skilled guitar player> skilled banjo player.

Stimulus is true and the question is Directly asking which of the options are true?

a) This is not correct since minority of skilled guitar player are skilled banjo player. This cannot be be greater majority, as discussed above. Rejected.

b)could be true but out of scope. Rejected.

c)could be true but out of scope. Rejected

d) Correct as described above.

e) opposite to stimulus. Rejected.

Most people who are skilled banjo players are also skilled guitar

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

Most people who are skilled banjo players are also skilled guitar

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards