Critical Reasoning

Frobisher, a sixteenth-century English explorer, had soil samples from Canada's Kodlunarn Island examined for gold content. Because high gold content was reported, Elizabeth I funded two mining expeditions. Neither expedition found any gold there. Modern analysis of the island's soil indicates a very low gold content. Thus the methods used to determine the gold content of Frobisher's samples must have been inaccurate.

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

(A) The gold content of the soil on Kodlunarn Island is much lower today than it was in the sixteenth century.

(B) The two mining expeditions funded by Elizabeth I did not mine the same part of Kodlunarn Island.

(C) The methods used to assess gold content of the soil samples provided by Frobisher were different from those generally used in the sixteenth century.

(D) Frobisher did not have soil samples from any other Canadian island examined for gold content.

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

OA E

Tough one :


Premise 1:F found high gold content
Premise 2:LIZ found 0 gold content
Premise 3:Moderns found low gold content

Therefore->F's method was flawed.


If there was added gold in the sample F examined then this undermines the main conclusion of the arguement. Hence my pick. E

I am not very sure though. Whats the source ?

Premise 1 - F's samples examined for high gold content
Premise 2 - 2 mining expeditions ordered - no gold found
Premise 3 - modern analysis indicated low gold content

Conclusion - Methods by which F's samples were examined were inaccurate

We have to find an assumption that links the Premises logically to the conclusion.

A - Actually goes against the conclusion, suggesting that earlier the gold content was high and not its low and tests also indicated the same. Therefore tests could not have been inaccurate.

B - if 2 expeditions did mining at different places, there could be a possibility that thye would have found the gold if they would have did mining at the same place !!

C - -Possible answer - talks about methods, but brings in the context of "generally followed methods" - If the methods were different from generally followed methods, then those methods might have produced different results.

D - Cannot tell if having more samples would have produced accurate results - far fetched

E - Works against the conclusion. If they would have added the gold to the samples, that would have made them inaccurate. Since it is not mentioned if they did or not, we cannot tell anything.

I will go with Choice C

Whats the OA ?

@champ0007

If we negate E, reasoning fails.

People believe that no one added any gold to the samples, so methods used are insufficent/inaccurate because they failed to determine the gold...

If they would have added gold, so the methods used would have been correct to not to find any gold!

IMO E..gud question..what is the source??

In power score's technical terms- this was a typical tough Defender question in which we prevent attack to the argument by actually proving falsity in the method used for final conclusion. This really wont click naturally at the first read until and unless u look the question with that perspective.

Ozlemg wrote: If they would have added gold, so the methods used would have been correct to not to find any gold!

Yeah ...i think I am getting it.

I think you meant if they would have added Gold to the samples, so the methods would have been ACCURATE to have reported high gold content..

But without Gold samples being added they reported High Gold content in the samples(when actually the soil had low gold content), which makes them Inaccurate..

Thanks !!!