columbian artifacts

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columbian artifacts

by pappueshwar » Sun Feb 12, 2012 8:58 am
HI experts,
please assist me in solving the below CR. i am just unable to make out how to solve this:


Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following:

(A) An ax head of black obsidian, unearthed from a kitchen midden
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
(C) A set of gold ear weights, ornamented with jasper pendants
(D) A black feather cape from a king's burial vault
(E) A multicolored woven sash found near the gravesite of a slave
Source: — Critical Reasoning |

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by sam2304 » Sun Feb 12, 2012 8:53 pm
Two conditions to determine the authenticity

1. unique scratch patterns because of earthquakes
2. darkening of surface color of magnesium in the soil.

Understand the question stem properly. What we have to find is with these condition which of the following items would be difficult to authenticate.

Other than D we will have darkening effects for every other items as they are in direct contact with the soil. Maybe not C but there is no information that the jewels are not kept in a safe. So we can move it as out of scope as information about where the item is kept is available for all other items. Hence D.

Hope this helps !!!
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by GMATGuruNY » Tue Feb 14, 2012 9:17 am
pappueshwar wrote:HI experts,
please assist me in solving the below CR. i am just unable to make out how to solve this:


Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following:

(A) An ax head of black obsidian, unearthed from a kitchen midden
(B) A pottery bowl with a red ocher design, found in the ruins of a temple
(C) A set of gold ear weights, ornamented with jasper pendants
(D) A black feather cape from a king's burial vault
(E) A multicolored woven sash found near the gravesite of a slave
I received a PM asking me to comment.

Sam2304 has nailed it.
The passage states that authentic artifacts exhibit a unique SCRATCH PATTERN and show a DARKENING IN SURFACE COLOR.
Neither of these qualities is applicable to a BLACK FEATHER CAPE, which is unlikely to show scratches or a darkening in color.

The correct answer is D.
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by karthikgmat » Fri Feb 24, 2012 12:30 am
Hi Mitch , I chose D.

But, I would like to know what kind of question is this? Is it an assumption or inference ?

And chosing D I had to assume that feather's will not be in touch with soil . Is it that way one should chose D here?

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by GMATGuruNY » Sat Feb 25, 2012 3:57 am
karthikgmat wrote:Hi Mitch , I chose D.

But, I would like to know what kind of question is this? Is it an assumption or inference ?

And chosing D I had to assume that feather's will not be in touch with soil . Is it that way one should chose D here?
This is an inference question, since we're using the passage to support the answer choices.
The passage offers criteria for judging the authenticity of an artifact.
Four of the answer choices could be judged according to these criteria; the correct answer could not.

D is correct because black feathers would be unable to show scratches or a darkening in color, the two criteria that the passage suggests can be used to judge the authenticity of an artifact.
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by GmatKiss » Sat Feb 25, 2012 5:56 am
IMO: D, an easy one!

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by mankey » Wed Mar 07, 2012 8:26 pm
Having interpreting option A. Someone please help, why this can not be the answer.

Regards.