According to the new estimates, the number of stars in the Milky Way

Question

According to the new estimates, the number of stars in the Milky Way galaxy has increased from 124 billion to 415 billion, while the number of stars in the Andromeda galaxy has doubled. With these updated figures, the number of stars in the Milky Way is still only 42% of the number of stars in the Andromeda galaxy. Prior to the new estimates, approximately how many times more stars did the Andromeda galaxy have compared to the Milky Way galaxy?

A. 2
B. 4
C. 5
D. 8
E. 16

A. 2
B. 4
C. 5
D. 8
E. 16

Bunuel · Accepted Answer

Official Solution:

According to the new estimates, the number of stars in the Milky Way galaxy has increased from 124 billion to 415 billion, while the number of stars in the Andromeda galaxy has doubled. With these updated figures, the number of stars in the Milky Way is still only 42% of the number of stars in the Andromeda galaxy. Prior to the new estimates, approximately how many times more stars did the Andromeda galaxy have compared to the Milky Way galaxy?

A. 2
B. 4
C. 5
D. 8
E. 16

A. 2
B. 4
C. 5
D. 8
E. 16

We are tasked with approximating, so let's proceed with that approach.

Consider using 400 billion instead of 415 billion, and 40% instead of 42%. This gives us: 400 billion = 0.4*(Andromeda's new estimate). Notice that the first approximation decreases the new estimate for the Andromeda galaxy, while the second approximation increases it. Therefore, these two approximations roughly balance each other out. Thus, from 400 billion = 0.4*(Andromeda's new estimate), we determine that Andromeda's new estimate is 1,000 billion. Given that the new estimates have doubled the numbers for the Andromeda galaxy, its old number was 500 billion.

Consequently, prior to the new estimates, the Andromeda galaxy had  \frac{500}{124} \approx 4  times more stars than the Milky Way galaxy.

Answer: B

gmatophobia · Answer

Given: Stars in the Milky Way increased from 124 billion to 415 billion.

Let's assume that the stars in Andromeda galaxy increased from x billion to 2x billion.

With these updated figures, the number of stars in the Milky Way is still only 42% of the number of stars in the Andromeda galaxy

Inference :  \frac{415}{2x }* 100 = 42

\frac{415}{x }* 50 = 42

x = \frac{415 * 50 }{ 42} \approx \frac{420 * 50 }{ 42} \approx 500

Therefore we can conclude that Andromeda galaxy had approximately 500 billion stars.

Question: Prior to the new estimates, approximately how many times more stars did the Andromeda galaxy have compared to the Milky Way galaxy?

Required Ratio =  \frac{500}{125} = 4

Option B

Edoua · Answer

Milky Way galaxy 124billion to 415 billion

Andromeda from x —— to Y =2x

Inference 415billion =( 42/100)Y
 —> Y =415*100/42
 —> Y=988 billion
then x= 494 billon

494/124 ~=4

Number of stars at Andromeda at the beginning was 4 times Milky Way galaxy

But the question was how many times —-more—…

I think the answer should be 3 but as it doesn’t lies to our answer choices I selected 4

Posted from my mobile device

Bunuel · Answer

No, you are wrong.

Here is my post from another topic addressing this issue:

Agree that it's confusing but check below:

Merriam Webster's  Dictionary of English Usage :

The argument in this case is that times more (or times larger, times stronger, times brighter, etc.) is ambiguous, so that "He has five times more money than you" can be misunderstood as meaning "He has six times as much money as you." It is, in fact, possible to misunderstand times more in this way, but it takes a good deal of effort. If you have $100, five times that is $500, which means that "five times more than $100" can mean (the commentators claim) "$500 more than $100," which equals "$600," which equals "six times as much as $100." The commentators regard this as a serious ambiguity, and they advise you to avoid it by always saying "times as much" instead of "times more." Here again, it seems that they are paying homage to mathematics at the expense of language. The fact is that "five times more" and "five times as much" are idiomatic phrases which have - and are understood to have - exactly the same meaning.

The "ambiguity" of times more is imaginary: in the world of actual speech and writing, the meaning of times more is clear and unequivocal. It is an idiom that has existed in our language for more than four centuries, and there is no real reason to avoid its use.

The "ambiguity" of  times more  is imaginary : in the world of actual speech and writing, the meaning of  times more  is clear and unequivocal. It is an idiom that has existed in our language for more than four centuries, and there is no real reason to avoid its use.

According to the new estimates, the number of stars in the Milky Way

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According to the new estimates, the number of stars in the Milky Way

Prep Toolkit

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

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My Rewards