GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 21 Nov 2019, 07:28

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Recent observations suggest that small, earthlike worlds form a very

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Senior Manager
Senior Manager
avatar
G
Joined: 04 Sep 2017
Posts: 291
Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 22 Sep 2019, 10:54
1
17
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

59% (02:27) correct 41% (02:39) wrong based on 550 sessions

HideShow timer Statistics

Recent observations suggest that small, earthlike worlds form a very low percentage of the planets orbiting stars in the galaxy other than the sun. Of over two hundred planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.

Which of the following, if true, would most weaken the above justification of the claim that earthlike worlds form a low percentage of the total number of planets?

A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

B. The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.

C. A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.

D. The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

E. The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.


CR03001.01
Intern
Intern
User avatar
B
Joined: 15 Feb 2017
Posts: 15
Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post Updated on: 29 Sep 2019, 02:36
2
1
The argument implies that sample of 200 planets is representative of planets in entire galaxy and that percentage of earth-like planets in the galaxy is very low. We need to weaken the claim.

A indicates that there are millions of other stars whose planets have not been detected. No one can sample millions of stars anyway, and this choice does not indicate why the sample taken is not representative.

B & E do not weaken the claim.

C is trap - it states that an earth-like planet is more likely to be found orbiting a sun-like star. In the absence of information about percentage of sun-like stars in the galaxy, it is not possible to comment on percentage of earth-like planets. Also, the argument says
Quote:
almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.


D correctly point out that smaller planets (in relation to the size of star) are hard to detect. Thus the 200 planets detected cannot truly indicate the percentage of earth-like stars (as it is likely that only bigger planets were detected while many earth-like planets lie undetected).

Originally posted by Rachna23 on 26 Sep 2019, 14:14.
Last edited by Rachna23 on 29 Sep 2019, 02:36, edited 1 time in total.
Manager
Manager
avatar
B
Joined: 20 Sep 2018
Posts: 86
GMAT 1: 590 Q47 V25
Re: Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 26 Sep 2019, 19:21
Dear Karishma,
Can you explain in more detail?
Regards,
Basim

Posted from my mobile device
Senior Manager
Senior Manager
avatar
G
Joined: 04 Sep 2017
Posts: 291
Re: Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 29 Sep 2019, 01:47
1
gmatt1476 wrote:
Recent observations suggest that small, earthlike worlds form a very low percentage of the planets orbiting stars in the galaxy other than the sun. Of over two hundred planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.

Which of the following, if true, would most weaken the above justification of the claim that earthlike worlds form a low percentage of the total number of planets?

A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

B. The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.

C. A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.

D. The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

E. The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.


CR03001.01


Official Explanation

Argument Evaluation

This question asks you to identify a claim that would, if true, weaken the justification for the conclusion that only a small percentage of the total number of planets in our galaxy are formed by earthlike worlds.

The only justification given for this conclusion is that, of the over 200 planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.

Any evidence suggesting that the planets the astronomers have detected may be unrepresentative of planets in general would weaken the justification this claim gives to the conclusion.

A. This may look like it weakens the justification. After all, if the total number of planets were significantly smaller than millions, then the sample size of over 200 planets would allow us to make the inference with more confidence. Nevertheless, particularly when accounting for the vagueness of the conclusion, the size of the sample is large enough to give us a reasonable degree of certainty. More importantly, though, note that the conclusion is restricted to planets orbiting stars in our galaxy. There is nothing in this answer choice to suggest that the planets it refers to are actually in our galaxy.

B. This choice strengthens the justification for the conclusion.

C. This choice does not weaken the justification for the conclusion. The only way it might do so is if it provided information showing that astronomers have mainly looked at planets orbiting an unrepresentative sample of stars, that is, a sample that is more heavily populated with planets orbiting stars that are smaller than most stars in the total star population. We are given no reason to believe this is the case.

D. Correct. This gives us a reason to think that the sample may be unrepresentative. Planets more earthlike in size may be less likely to be detected than the much larger stars that astronomers have detected.

E. This claim strengthens, rather than weakens, the argument. It implies that the astronomers' detection methods would not have inadvertently underrepresented the number of earthlike worlds.

The correct answer is D.
Intern
Intern
avatar
B
Joined: 20 Jan 2017
Posts: 33
Re: Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 13 Oct 2019, 13:55
What is with the wording of the new edition of CR questions? I feel like the answer choices are extremely difficult to comprehend.

What does this even mean?
A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

Astronomers have not tried to detect planets out of the millions of planets that orbit the many number of stars? Isn't it supposed to be trying to detect earth-like planets?

Moreover, the OG explanation for why A is incorrect includes "More importantly, though, note that the conclusion is restricted to planets orbiting stars in our galaxy. There is nothing in this answer choice to suggest that the planets it refers to are actually in our galaxy."
Where does the passage explicitly narrow in on our galaxy, and exclude other galaxies?
Senior Manager
Senior Manager
avatar
S
Joined: 17 Sep 2016
Posts: 311
Re: Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 15 Oct 2019, 06:38
1
hi experts,
I have the same problem with A , please help

khan0210 wrote:
What is with the wording of the new edition of CR questions? I feel like the answer choices are extremely difficult to comprehend.

What does this even mean?
A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

Astronomers have not tried to detect planets out of the millions of planets that orbit the many number of stars? Isn't it supposed to be trying to detect earth-like planets?

Moreover, the OG explanation for why A is incorrect includes "More importantly, though, note that the conclusion is restricted to planets orbiting stars in our galaxy. There is nothing in this answer choice to suggest that the planets it refers to are actually in our galaxy."
Where does the passage explicitly narrow in on our galaxy, and exclude other galaxies?
Manager
Manager
avatar
B
Joined: 09 Nov 2018
Posts: 91
CAT Tests
Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post Updated on: 16 Oct 2019, 13:56
1
VeritasKarishma GMATNinja nightblade354 and other experts please help us out here!
Why is A wrong? Even after reading the OG explanation I'm not at all convinced. A seems fair. A vs D is hard. They're so close.
Any help would be appreciated. Thanks in advance :)

Originally posted by RK007 on 16 Oct 2019, 07:29.
Last edited by RK007 on 16 Oct 2019, 13:56, edited 1 time in total.
Manager
Manager
avatar
S
Joined: 29 Oct 2015
Posts: 233
Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 16 Oct 2019, 13:24
1
gmatt1476 wrote:
Recent observations suggest that small, earthlike worlds form a very low percentage of the planets orbiting stars in the galaxy other than the sun. Of over two hundred planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.

Which of the following, if true, would most weaken the above justification of the claim that earthlike worlds form a low percentage of the total number of planets?

A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

B. The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.

C. A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.

D. The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

E. The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.


CR03001.01


VeritasKarishma GMATNinja generis GMATGuruNY daagh mikemcgarry
Can you please explain why option A is wrong and option C is correct ?
CR & LSAT Forum Moderator
User avatar
V
Status: He came. He saw. He conquered. -- Studying for the LSAT -- Corruptus in Extremis
Joined: 31 Jul 2017
Posts: 809
Location: United States (MA)
Concentration: Finance, Economics
Reviews Badge
Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 19 Oct 2019, 10:16
1
New Video: Fair warning, I do a better job of explaining why A is wrong then explaining why D is correct!

Also, NEVER MAKE ASSUMPTIONS TO JUSTIFY ANSWERS! THIS IS WHY I HATE THIS QUESTION!



_________________
D-Day: November 18th, 2017

My CR Guide: Here

My RC Guide: Here

Need an expert to grade your AWA? Go: Here

Want to be a moderator? We may want you to be one! See how: Here
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 9799
Location: Pune, India
Re: Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 23 Oct 2019, 07:04
gmatt1476 wrote:
Recent observations suggest that small, earthlike worlds form a very low percentage of the planets orbiting stars in the galaxy other than the sun. Of over two hundred planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun.

Which of the following, if true, would most weaken the above justification of the claim that earthlike worlds form a low percentage of the total number of planets?

A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

B. The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.

C. A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.

D. The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

E. The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.


CR03001.01


Claim: Small planets like Earth are a small percent of planets orbiting stars (other than Sun) in our galaxy.
- Of 200 planets examined, almost all are much larger than Earth and their star much smaller than Sun.

Which would weaken the justification of the claim?

A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

This says that there are millions of planets which have not been examined. Nevertheless, the sample of 200 examined show a particular characteristic. Nothing says that the sample is not representative. Sampling is a valid technique if sample is a good representation of the population. Also, we don't know whether the stars being talked about are from this galaxy.

B. The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.

This supports our claim.

C. A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.

We don't know how many stars are Sun-like. If Sun-like stars form a very low percentage, Earth like planets will form a very low percentage too. We need to weaken the justification i.e. the observation.

D. The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

This says that our sample may not be representative of the population. If smaller planets are harder to detect, only large planets might have been detected. Hence, of the 200 planets, most were large because they were easy to find. Perhaps, smaller planets are harder to find and hence were not a part of the 200.

E. The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.

This tells us that small planets would have been easy to detect too. This helps our claim.

Answer (D)
_________________
Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
Manager
Manager
avatar
G
Joined: 11 Jul 2016
Posts: 91
Location: India
Concentration: General Management, Technology
GPA: 4
GMAT ToolKit User Premium Member
Re: Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 23 Oct 2019, 11:40
Answer: D

Evidence : 200 planets detected, All those are bigger than Earth.
Conclusion : Earth-like planets form very low % of all planets.

Quote:
A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

Can we be sure of what could be the size of those planets if at all astronomers attempted to detect them ? NO

Quote:
B. The best current astronomical theories predict that almost all planets around other stars are probably hundreds of times larger than the earth.
This one strengthens the argument.

Quote:
C. A planet orbiting a star similar to the sun would be more likely to be earthlike in size than would a planet orbiting a much smaller star.
Argument is about planet size irrespective of their respective sun's size.

Quote:
D. The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

Makes sense. Those smaller planets (earth-like) are more difficult to detect. Hence, we cannot come to any conclusion on how many such planets are present.

Quote:
E. The observations would have detected any small, earthlike worlds orbiting the stars around which larger planets have been detected.
This one too strengthens the argument as it says that the observations reflect the actual presence of planets.
_________________
Please give Kudos if you find this post useful.
GMAT Club Verbal Expert
User avatar
D
Status: GMAT and GRE tutor
Joined: 13 Aug 2009
Posts: 2924
Location: United States
GMAT 1: 780 Q51 V46
GMAT 2: 800 Q51 V51
GRE 1: Q170 V170
Re: Recent observations suggest that small, earthlike worlds form a very  [#permalink]

Show Tags

New post 28 Oct 2019, 20:23
1
khan0210 wrote:
What is with the wording of the new edition of CR questions? I feel like the answer choices are extremely difficult to comprehend.

What does this even mean?
A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

Astronomers have not tried to detect planets out of the millions of planets that orbit the many number of stars? Isn't it supposed to be trying to detect earth-like planets?

Moreover, the OG explanation for why A is incorrect includes "More importantly, though, note that the conclusion is restricted to planets orbiting stars in our galaxy. There is nothing in this answer choice to suggest that the planets it refers to are actually in our galaxy."
Where does the passage explicitly narrow in on our galaxy, and exclude other galaxies?

RK007 wrote:
and other experts please help us out here!
Why is A wrong? Even after reading the OG explanation I'm not at all convinced. A seems fair. A vs D is hard. They're so close.
Any help would be appreciated. Thanks in advance :)

I agree that some of these new questions are tricky! As usual, the exact language of the passage, question, and answer choices will help to eliminate the incorrect answers.

Let's first take a look at the passage:
  • Conclusion: "Recent observations suggest that small, earthlike worlds form a very low percentage of the planets orbiting stars in the galaxy other than the sun."
  • Justification for this conclusion: "Of over two hundred planets that astronomers have detected around other stars, almost all are hundreds of times larger and heavier than the earth and orbit stars much smaller than the sun."

The question asks which answer choice would "would most weaken the above justification of the claim that earthlike worlds form a low percentage of the total number of planets." There are a couple of things of note in this question:
  • It points us toward the justification for the claim. So, we are trying to weaken that particular piece of the passage, or the link between the justification and the passage's conclusion.
  • We need to find the answer that most weakens the justification -- this leaves open the possibility that multiple answer choices weaken the justification. We may need to eliminate the weaker weakeners (is your head spinning yet?), and keep the strongest weakener.

Take a look at (A):
Quote:
A. There are millions of planets orbiting stars around which astronomers have not attempted to detect planets.

To clarify the meaning of this sentence, note that the things "around which" astronomers have not attempted to detect planets are the "stars" mentioned earlier in the sentence. In other words, astronomers haven't attempted to detect planets around certain stars, and around these stars are millions of planets.

At a glance, this seems to weaken the force of the justification in the passage! Astronomers have only detected 200 planets, so perhaps these are not representative of the millions of other planets out there. Maybe a higher percentage of the not-yet-detected planets are earthlike, which would undermine the author's conclusion that a very low percentage of planets in the galaxy are small and earthlike.

After a bit more thought, though (A) is a pretty weak weakener (for the exact reason mentioned in the OE, which I'll try to explain a bit).

The author's conclusion is focused on the planets in our galaxy, while (A) just tells us that we haven't yet detected a bunch of planets out there somewhere in space. Maybe the 200 planets that were already detected are all within our galaxy, while the millions of undetected planets are outside of our galaxy. In this case, the justification in the passage would not be weakened very much, because the data from the 200 planets would be much more relevant to the conclusion than would the new information provided by (A).

We don't know for sure whether this is true, so we just have to keep in mind that (A) may weaken the justification provided in the passage, or it may not.

Now take a look at (D):
Quote:
D. The smaller a planet is relative to the star it orbits, the more difficult it is for astronomers to detect.

The justification in the passage for the author's conclusion is that "almost all" of the 200 planets detected by astronomers are much heavier than the earth and orbit much smaller stars. From this, the author concludes that a very low percentage of planets in the galaxy are small/earthlike.

But wait -- what if astronomers just suck at detecting small/earthlike planets in the first place? Then the justification (that almost all of the detected planets are big) doesn't mean much. It just shows that we are good at detecting one kind of planet, and bad at detecting another. The link between the 200 detected planets and the conclusion is pretty much destroyed.

(D), if true, makes the justification provided in the passage kind of worthless. (A), in comparison, is the weaker weakener -- because we don't know whether the millions of undetected planets are in our galaxy, we don't know how much it impacts the force of the passage's justification.

For this reason, (A) is out and (D) is the right answer.

I hope that helps!
_________________
GMAT/GRE tutor @ www.gmatninja.com (we're hiring!) | GMAT Club Verbal Expert | Instagram | Blog | Bad at PMs

Beginners' guides to GMAT verbal: RC | CR | SC

YouTube LIVE verbal webinars: all videos by topic

SC articles & resources: How to go from great (760) to incredible (780) on GMAT SC | That "-ing" Word Probably Isn't a Verb | That "-ed" Word Might Not Be a Verb, Either | No-BS Guide to GMAT Idioms | "Being" is not the enemy | WTF is "that" doing in my sentence?

RC, CR, and other articles & resources: All GMAT Ninja articles on GMAT Club | Using LSAT for GMAT CR & RC |7 reasons why your actual GMAT scores don't match your practice test scores | How to get 4 additional "fake" GMAT Prep tests for $29.99 | Time management on verbal

SC & CR Questions of the Day (QOTDs), featuring expert explanations: All QOTDs | Subscribe via email | RSS

Need an expert reply? Hit the request verbal experts' reply button; be specific about your question, and tag @GMATNinja. Priority is always given to official GMAT questions.
GMAT Club Bot
Re: Recent observations suggest that small, earthlike worlds form a very   [#permalink] 28 Oct 2019, 20:23
Display posts from previous: Sort by

Recent observations suggest that small, earthlike worlds form a very

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne