Critical Reasoning

Astronomer Michael Bolte has found considerable variation in the ages of globular clusters. One of the clusters studied by Bolte is 2 billion years older than most other clusters in the galaxy, while another is 2 billion years younger. A colleague of Bolte contends that the cluster called Palomar 12 is 5 billion years younger than most other globular clusters.

If Bolte and his colleague are both correct, it can be
inferred that the globular cluster Palomar 12 is
approximately

(A) 5 billion years younger than any other cluster in
the galaxy
(B) the same age as most other clusters in the
galaxy
(C) 7 billion years younger than another cluster in
the galaxy
(D) 12 billion years younger than most other
clusters in the galaxy
(E) 2 billion years younger than most other clusters
in the galaxy

This is tough!!

i will go with C..


source with OA please!!



thx

This is actually a Reading Comp Q on a paper based GMAT test.

I will tell the OA after a few more responses.

chidcguy wrote:Astronomer Michael Bolte has found considerable variation in the ages of globular clusters. One of the clusters studied by Bolte is 2 billion years older than most other clusters in the galaxy, while another is 2 billion years younger. A colleague of Bolte contends that the cluster called Palomar 12 is 5 billion years younger than most other globular clusters.

If Bolte and his colleague are both correct, it can be
inferred that the globular cluster Palomar 12 is
approximately

(A) 5 billion years younger than any other cluster in
the galaxy
(B) the same age as most other clusters in the
galaxy
(C) 7 billion years younger than another cluster in
the galaxy
(D) 12 billion years younger than most other
clusters in the galaxy
(E) 2 billion years younger than most other clusters
in the galaxy

It's (C).

5 + 2 = 7... seems pretty straightforward!



If Palomar 12 is 5 billion years younger than most other globular clusters, and there's a cluster that's 2 billion years older than most other globular clusters, then it must be true that Palomar 12 is 7 billion years younger than the older cluster.

Stuart,

I though about it. But My concern was what if Palomar 12 is the cluster Bolte is referring to as the cluster that is 2 years younger than most other clusters.

Thats why I thought we can say for certain that the Palomar 12 cluster is 2 yrs younger than most other clusters.

I see that the Q starts with Bolte and his colleague are true in what they say, Is this excluding the possibility that they are both referring to the same Palomar cluster??

chidcguy wrote:Stuart,

I though about it. But My concern was what if Palomar 12 is the cluster Bolte is referring to as the cluster that is 2 years younger than most other clusters.

Thats why I thought we can say for certain that the Palomar 12 cluster is 2 yrs younger than most other clusters.

I see that the Q starts with Bolte and his colleague are true in what they say, Is this excluding the possibility that they are both referring to the same Palomar cluster??

If they're both correct, then it's impossible for them to be speaking about the same cluster, since they give contradictory facts (i.e. there's no way that Palomar 12 could be BOTH 5 billion years younger than most other clusters AND 2 years older/younger than most other clusters).

I would go with C,
If both Bolte and his colleagues refer to the same globular, it cannot be true,
So that they must refer to two different globular

premises can be summerize as below

Bolte:
A, 1 globular 2 B years older than most globular clusters
B, 1 globular 2 B years younger than most globular clusters

Bolte's colleague
C, 1 globular 5 B years younger than most globular clusters

so that the globular 5 B years younger than most globuler clusters comparing with A will be 7 B years

IMO: A

2 years younger and 5 years younger = maximum of 5 years younger

I just got to this one in OG 10 and still don't understand how they arrive at an answer of C.

Say the older cluster studied by Bolte is 10 billion years old. Then "most other clusters" are 8 billion years old. That would make the younger cluster studied by Bolte 6 billion years old.

Therefore, the cluster studied by Bolte's colleague, which is 5 billion years younger than "most other clusters", is 3 billion years old.

That would put the cluster studied by Bolte's colleague, at most, 3 billion years younger than any cluster in the galaxy.

The cluster studied by Bolte's colleague is 7 billion years younger than the oldest cluster in the galaxy, but the answer choice reads "7 billion years younger than another cluster in the galaxy." Of course, I am interpreting "another" to mean "any other". Is that where I am wrong?

Normally I would dismiss this as an awful question, but it is in the OG.

if u draw the pic , this becomes v easy

let the avg age of star - 20yr( we leave billion here as not necessary)

oldest - 22yrs

youngest -18 yrs (as cal by bolte)


Assistant found P12 as age - 15yr

put in seq

15 18 20 22..................

So if u see options ..........C fits easily.

Stuart,pls, help

I think E is correct because it is old information paraphrased.

C is not true for sure.. How do you know that there is one cluster 7 year older than No 12 cluster. we can not prove this. the correct answer MUST BE TRUE. "most" is meaningless to prove C.

ok, C is correct
but E is also correct.

IMO C!!

I agree with you guys. I also think that the right answer is A.