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CR Using Assumption Negation

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CR Using Assumption Negation

by gmatrant » Tue Jan 24, 2012 11:38 am
Hi,

Can you please help me with applying assumption negation technique on this question.

The average hourly wage of television assemblers in Vernland has long been significantly lower than that in neighboring Borodia. Since Borodia dropped all tariffs on Vernlandian televisions three years ago, the number of televisions sold annually in Borodia has not changed. However, recent statistics show a droip in the number of television assemblers in Borodia. Therefore, updated trade statistics will probably indicate that the number of televisions Borodia imports annually from Vernland has increased.

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

A. The number of television assemblers in Vernland has increased by at least as much as the number of television assemblers in Borodia has decreased.

B. Televisions assembled in Vernland have features that televisions assembled in Borodia do not have.

C. The average number of hours it takes a Borodian television assembler to assemble a television has not decreased significantly during the past three years.

D. The number of televisions assembled annually in Vernland has increased significantly during the past three years.

E. The difference between the hourly wage of television assemblers in Vernland and the hourly wage of television assemblers in Borodia is likely to decrease in the next few years

I was stuck between A & C. I was trying to apply the negation technique on A. C is the answer and did not have an issue negating it. Can someone tell me how to negate A and also use it against the problem statement to prove that it does not destroy the problem.

If you are wondering what Assumption negation technique is , please refer this link below to get better clarity or create a new thread on the same forum to discuss the same.
https://www.manhattangmat.com/forums/cr- ... 11293.html


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gmatrant
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by David@VeritasPrep » Tue Jan 24, 2012 12:59 pm
Choice A says, "The number of television assemblers in Vernland has increased by at least as much as the number of television assemblers in Borodia has decreased."

To negate this you add a "not" to the main verb. SO,

"The number of television assemblers in Vernland has NOT increased by at least as much as the number of television assemblers in Borodia has decreased."

Now put that into English, "It may be the case that the decrease in the number of TV assemblers in Borodia exceeds the increase in the number of TV assemblers in Vernland." Or we can say, "What if the total number of TV assemblers in Vernland and Borodia combined has decreased"? That is what is really said here right, if we negate B? More TV assemblers lost in Borodia than gained in Vernland?

Okay so let's look at the question with this in mind,

the conclusion is: "the number of televisions Borodia imports annually from Vernland has (probably) increased." and the evidence is "Vernland labor is cheaper, # of assemblers in Borodia has decreased, and number of TVs sold in Borodia has not changed."

Now what if we have fewer total TV assemblers? Well, technology may have improved so each assembler makes more TVs. So Choice A is not required. We do not need to have the same number of assemblers in order to keep selling the same number of TVs. More productivity!

Does that help?
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by MBACenter » Tue Jan 24, 2012 1:00 pm
gmatrant wrote:Hi,

Can you please help me with applying assumption negation technique on this question.

The average hourly wage of television assemblers in Vernland has long been significantly lower than that in neighboring Borodia. Since Borodia dropped all tariffs on Vernlandian televisions three years ago, the number of televisions sold annually in Borodia has not changed. However, recent statistics show a droip in the number of television assemblers in Borodia. Therefore, updated trade statistics will probably indicate that the number of televisions Borodia imports annually from Vernland has increased.

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

A. The number of television assemblers in Vernland has increased by at least as much as the number of television assemblers in Borodia has decreased.

B. Televisions assembled in Vernland have features that televisions assembled in Borodia do not have.

C. The average number of hours it takes a Borodian television assembler to assemble a television has not decreased significantly during the past three years.

D. The number of televisions assembled annually in Vernland has increased significantly during the past three years.

E. The difference between the hourly wage of television assemblers in Vernland and the hourly wage of television assemblers in Borodia is likely to decrease in the next few years

I was stuck between A & C. I was trying to apply the negation technique on A. C is the answer and did not have an issue negating it. Can someone tell me how to negate A and also use it against the problem statement to prove that it does not destroy the problem.

If you are wondering what Assumption negation technique is , please refer this link below to get better clarity or create a new thread on the same forum to discuss the same.
https://www.manhattangmat.com/forums/cr- ... 11293.html


Thanks
gmatrant
Hello!

Before tackling the question, let me explain the negation technique a little bit more formally. It is a useful technique, but with a bit of deeper understanding you can apply the core concept with more flexibility.

Say that given proposition p and proposition q, if p, then q. This means that knowing p is true is SUFFICIENT to know that q is true (hence "p is sufficient to know q").

Consequently, if q is NOT true, then we will know that p is not true, because if we had p we would also have q. Thus we say that q is NECESSARY for p (no p without q).

To sum it up, "p is sufficient to know q" is the same statement as "q is necessary for p."

Now, let's suppose that assumption A is necessary in order for conclusion C to be true. This is the same as saying that C is sufficient to know A, since if C is true, then A must be true. Therefore:

1. If A is false, then C must be false.
2. If C is true, then A must be true.

So there are really two ways you can apply this logical principle.

First, you can go through the answer choice and ask, "If this statement is false, will it make the conclusion necessarily false?" If so, then the answer choice contains a necessary assumption.

Alternatively, you can read the stimulus statements and take the conclusion and all premises as true. Then as you read the answer choices, ask yourself, "If that conclusion is true, does this statement logically follow?" It will have the same effect as the negation technique, as we have just logically demonstrate.

In sum, Assumption questions can be treated the same as Draw a Conclusion or Infer questions, even if their appearance is usually quite different.

NOW... on to this question!

The conclusion is that the drop in the number of television assemblers in Borodia is due to an increase in the number of televisions Borodia imports annually from Vernland.

If this is true, then there cannot be a different reason why the number of assemblers has dropped that would NOT imply the same number of televisions are manufactured in Borodia despite a smaller number of assemblers. Thus do we infer C from the stimulus.

(If x is the cause of y, then z cannot be the cause of y.)

(On the other hand, supposing Vernland WERE exporting more TVs to Borodia, why should that mean they need more TV assemblers? Perhaps their assemblers have simply become more efficient... or concurrently stopped selling in other markets.)
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