Astronomers have long thought that the irregularity in the orbit of th

Question

Astronomers have long thought that the irregularity in the orbit of the planet Neptune was adequately explained by the gravitational pull exerted on Neptune by the planet Pluto. The most recent observations of Pluto, however, indicate that this planet is much too small to exert the amount of gravitational pull on Neptune that astronomers once thought it did.

If the statements above are true, they provide the most support for which one of the following?

(A) Neptune is somewhat larger than scientists once believed it to be.

(B) The orbit on Neptune is considerably more irregular than scientists once thought it was.

(C) There exists another, as yet undiscovered planet with an orbit beyond that of Pluto.

(D) The gravitational pull of Pluto is not the sole cause of Neptune’s irregular orbit.

(E) Further observations of Pluto will eventually show it to be even smaller than it is now thought to be.

Bhuvan.deshwal · Answer

I disagree with the OA as Pluto turns out not to be any reason for Neptune's irregular orbit since the argument states "planet is much too small to exert the amount of gravitational pull on Neptune that astronomers once thought it did".
And the option d indicates that Pluto's pull is not the sole reason to cause the irregularity, but it is one.

sobby · Answer

Let me try for this:
D.The gravitational pull of Pluto is not the sole
cause of Neptune’s irregular orbit.----it means other than pluto there are some forces that are contributing in the irregular orbit.

Argument says that planet(pluto) is much too small to exert the amount of
gravitational pull on Neptune...it does not say that pluto is not causing any gravitational pull..
Gpull = gravitational pull required for irregular orbit ..
Now GPLU = Gravitational pull by pluto ..a
according to argument,
GPULL > GLPU
to make equal ..
GPULL = unknown forces + GPLU .
What D says ..pluto is not the sole reason ........

AkshdeepS · Answer

If the statements above are true, they provide the most support for which one of the following?

(A)  Neptune is somewhat larger  than scientists once believed it to be.  Not mentioned

(B)  The orbit on Neptune  is considerably  more irregula r than scientists once thought it was.  Not mentioned

(C) There exists  anothe r, as yet  undiscovered planet  with an orbit beyond that of Pluto.  Not mentioned

(D) The gravitational pull of Pluto is not the sole cause of Neptune’s irregular orbit. 
 
(E) Further observations of  Pluto  will eventually show it to be  even smaller than  it is now thought to be.  Not mentioned

It's (D), alternate cause.

GMATBusters · Answer

Hi  GMATNinja ,  abhimahna

"The most recent observations of Pluto, however, indicate that this planet is much too small to exert the amount of gravitational pull on Neptune that astronomers once thought it did" -Doesn't this means, that scientist at later stage realized that Pluto is smaller than it is thought to be?

GMATBusters · Answer

I got my mistake. Option E says something about future, So it cannot be inferred from the stimulus, hence it is not right.

abhimahna · Answer

Hey gmatbusters , Yes that is correct. You cannot infer about the future based on current information. Moreover, option E is stating a similar fact about the size. As an inference of the current argument, we need to show that there size isn't directly/only impacting the orbit. This is what option D is doing. Hence, D is the correct answer. I hope that helps

GMATBusters · Answer

Hi
I don't think we need to strengthen the argument" in this question.
 "If the statements above are true, they provide the most support for which one of the following?"
I believe this is a Must be true / inference question.

PS: I am an amateur in CR, So I might be wrong. Please correct my understanding.

abhimahna · Answer

Yes, that is correct. This is an inference question and that was a typo.

VerbalBot · Answer

Automated notice from GMAT Club VerbalBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

Astronomers have long thought that the irregularity in the orbit of th

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

Astronomers have long thought that the irregularity in the orbit of th

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