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SVP
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26 Aug 2013, 18:45
2
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Difficulty:

55% (hard)

Question Stats:

62% (01:51) correct 38% (02:02) wrong based on 704 sessions

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Canadian mining company Bre-X had soil samples from its Busang project examined for gold content in 1992. The positive news of gold being present attracted a range of investors - from unsophisticated individuals to saavy mining professionals - to invest in the Busang project. After years of successful promotion, the truth about this worthless property slowly emerged early in 1997 and drove Bre-X stock prices nearly to zero. A repeat analysis of the soil in 1997 indicated very low gold content. Thus the methods used to determine the gold content in 1992 must have been inaccurate.

Which of the following is an assumption on which the argument depends?

(A) The gold content of the soil in Busang was much lower in 1997 than it was in 1992.

(B) After 1992, Bre-X was not mining in the same areas of Busang that the sample was taken from.

(C) The methods used to assess gold content of the soil samples in 1992 were different from those generally used during that time.

(D) Bre-X did not have soil samples from any other Busang property examined for gold content.

(E) Gold was not added to the soil samples collected by Bre-X before the samples were examined.

Original Source: Practice Pill Platform
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26 Aug 2013, 19:15
6
GMATPill wrote:
Canadian mining company Bre-X had soil samples from its Busang project examined for gold content in 1992. The positive news of gold being present attracted a range of investors - from unsophisticated individuals to saavy mining professionals - to invest in the Busang project. After years of successful promotion, the truth about this worthless property slowly emerged early in 1997 and drove Bre-X stock prices nearly to zero. A repeat analysis of the soil in 1997 indicated very low gold content. Thus the methods used to determine the gold content in 1992 must have been inaccurate.

Which of the following is an assumption on which the argument depends?

(A) The gold content of the soil in Busang was much lower in 1997 than it was in 1992.

(B) After 1992, Bre-X was not mining in the same areas of Busang that the sample was taken from.

(C) The methods used to assess gold content of the soil samples in 1992 were different from those generally used during that time.

(D) Bre-X did not have soil samples from any other Busang property examined for gold content.

(E) Gold was not added to the soil samples collected by Bre-X before the samples were examined.

Conclusion: Thus the methods used to determine the gold content in 1992 must have been inaccurate.

Premise: Conflicting predictions of gold content in 1992 and 1997

Pre-thinking: The author is strongly blaming the Method to be inaccurate. So anything in the answer choices which helps us support that the METHOD is the only one which is INACCURATE and not anything else affecting the protocol would be the correct answer

POE

A- if the gold content was lower in 1997 than in 1992-it supports the fact the method was accurate in estimating gold in 1992
B- If they were no mining in the same area, it does not affect the conclusion of methods being inaccurate
C- If the methods were different, again the methods could have different sensitivity ranges to estimate gold content and still being accurate in its own ways
D- Even if there were soil samples not analyzed from different Busang properties, it cannot verify the accuracies of any method
E- Now, if the Gold was not added to the soil samples before estimation in 1992, it gives support to the fact that it was the method and nothing in the protocol which led to inaccurate results.

negating E- gold was ADDED to the soil sample destroys the conclusion that it was the addition of gold prior to the analysis which led to inaccurate results and not the method per say!

hence E

Waiting official explanation from Gmat-pill

thanks
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27 Aug 2013, 02:12
Difficult question for me, GMAT-pill waiting for official explanation.
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27 Aug 2013, 07:46
doesnt look like a good question. GmatPill please give us the explanation.
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27 Aug 2013, 08:40
1
Premises:
1992, Project X = soil samples were examined for gold content --> good result.
1997, other soil samples were examined again, proving that inadequate gold content.

Conclusion: methods employed to determine gold content in 1992 is inaccurate

Prethinking: Assumption is that the soil samples must be representative of the population
OR the gold content is equally distributed in the mine.

Hence, the company did not distort the soil samples by adding gold into.

-->E
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27 Aug 2013, 19:32
Agree why E is correct ans. However, even B seems correct.

Mining could have led to decrease in gold content. How can B be ruled out?
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27 Aug 2013, 20:53
Answer (B) provides another explanation to the finding which seriously weakens the argument. The correct answer choice for this question has to be the "defender" assumption by stating that the ONLY explanation to this is the method used was inaccurate.
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01 Aug 2014, 05:22
Blasted by the question and stunned to silence by options and OA

Regards
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23 Apr 2016, 10:43
The answer has to be option E. Looks straight forward
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13 Sep 2017, 04:43
naaangerleyanyetei wrote:
Difficult question for me, GMAT-pill waiting for official explanation.

Conclusion: methods employed to determine gold content in 1992 is inaccurate

Assumption is that the soil samples must be representative of the population
OR the gold content is equally distributed in the mine.

Hence, the company did not distort the soil samples by adding gold into. E
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07 Jan 2018, 00:53
Using POE, test takers can choose E.
Both the argument and E are common patterns.
E indicates that the sample is not distorted -> a common pattern as an assumption.
The conclusion of the argument is that the method X is incorrect b/c of...
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07 Jan 2018, 03:27
The correct answer is option C

Here the conclusion is king.

The conclusion wording focuses on the METHOD accuracy used.

Option E looks like a trap from the test maker. The correct answer MUST BE True.

Option E is probably true, but does not have to be true as it is too specific IMO. The conclusion says "methods", but option E only highlights one method.

If you negate option C, you get the "Methods" used were not different from those used during that time. Meaning that the "methods" were as accurate as most methods used in 1992.

This weakens the argument in the conclusion that the methods used in 1992 were inaccurate.

I take option C

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07 Jan 2018, 09:51
There is a similar question in OG . The answer is indeed E.

If you use negation technique the assumption falls apart.
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07 Jan 2018, 20:53
Turkish wrote:
There is a similar question in OG . The answer is indeed E.

If you use negation technique the assumption falls apart.

I maintain that option E is a vert good trap.

Also when we look at the option E critically, is the conclusion really weakened when option E is negated?

Negating option E means Gold was actually applied to samples before measurement was taken.

If anything, this even strengthens the conclusion that measurement methods used in 1992 were inaccurate.

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07 Jan 2018, 21:03
Juz2play wrote:
Answer (B) provides another explanation to the finding which seriously weakens the argument. The correct answer choice for this question has to be the "defender" assumption by stating that the ONLY explanation to this is the method used was inaccurate.

This is also a trap.

Option B says that the company was MINING (what??) In the same AREA (distraction: conclusion was concerned about method accuracy )

While this is probably true, it does not have to be true.

What if they were mining copper in the same are after 1997?

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07 Jan 2018, 21:08
Aussy2000 wrote:
Turkish wrote:
There is a similar question in OG . The answer is indeed E.

If you use negation technique the assumption falls apart.

I maintain that option E is a vert good trap.

Also when we look at the option E critically, is the conclusion really weakened when option E is negated?

Negating option E means Gold was actually applied to samples before measurement was taken.

If anything, this even strengthens the conclusion that measurement methods used in 1992 were inaccurate.

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C is incorrect my friend, if the two methods (one in 1997, and one in 1992) are different, how can we conclude the method in 1992 is inaccurate.
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08 Jan 2018, 16:03
HBSdetermined is correct in that if you assume the reverse - that gold was added to the samples - you wouldn't conclude that the 1992 method must have been inaccurate. Even if you just introduced the possibility that the gold samples might have been tampered with, you couldn't say with certainty that the 1992 methods were inaccurate, which is what the argument does.

(Also, answer E is what actually happened in the case of Bre-X - they tampered with the samples....knowing this useless piece of information makes this question much easier.)
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08 Jan 2018, 16:35
jps245 wrote:
HBSdetermined is correct in that if you assume the reverse - that gold was added to the samples - you wouldn't conclude that the 1992 method must have been inaccurate. Even if you just introduced the possibility that the gold samples might have been tampered with, you couldn't say with certainty that the 1992 methods were inaccurate, which is what the argument does.

(Also, answer E is what actually happened in the case of Bre-X - they tampered with the samples....knowing this useless piece of information makes this question much easier.)

hello, I still do not get your analysis of the question. It is still confusing to me.
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Updated on: 08 Jan 2018, 17:31
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Hi chesstitans

If there was a possibility that gold was added to the samples before the 1992 test (meaning that the samples didn't contain gold naturally, that someone added gold to them), then there is another possible explanation for the difference in measurements between 1992 and 1997.

Since this gives another possible explanation for the result, you can't conclude from this that the method MUST have been inaccurate. In the case in which someone added gold to the sample for the 1992 test, the method could have still been accurate, (if someone added gold, then the soil actually did contain that much gold and was measured correctly).

Therefore, to conclude that the method must have been inaccurate, you have to assume that no one added gold to the sample for the 1992 test. Or else, there could have been another cause for the difference.

Sometimes it helps for questions like this when such a definitive statement is made (this was the result, so this MUST have been the cause...) to consider whether any of the choices involve another event that could have caused the result. If it does, then the argument makes an implicit assumption that it didn't take place.

An example: if a coworker was late today and you argued it MUST be because there was traffic, you're implicitly assuming that he didn't leave his house an hour too late.

Sorry for the long explanation. Hope this helps

Originally posted by jps245 on 08 Jan 2018, 17:01.
Last edited by jps245 on 08 Jan 2018, 17:31, edited 1 time in total.
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08 Jan 2018, 17:31
jps245 wrote:
Hi chesstitans

If there was a possibility that gold was added to the samples before the 1992 test (meaning that the samples didn't contain gold naturally, that someone added gold to them), then there is another possible explanation for the difference in measurements between 1992 and 1997.

Since this gives another possible explanation for the result, you can't conclude from this that the method MUST have been inaccurate. In the case in which someone added gold to the sample for the 1992 test, the method could have still been accurate (if someone added gold, then the soil actually did contain that much gold and was measured correctly).

Therefore, to conclude that the method must have been inaccurate, you have to assume that no one added gold to the sample for the 1992 test. Or else, there could have been another cause for the difference.

Hope this helps

So I guess C is the answer?

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