abhi758 wrote:
Official Guide for GMAT Verbal Review, 2nd EditionPractice Question
Question No.: 37
Page: 130 Which of the following most logically completes the argument?
Although the pesticide TDX has been widely used by fruit growers since the early 1960’s, a regulation in force since 1960 has prohibited sale of fruit on which any TDX residue can be detected. That regulation is about to be replaced by one that allows sale of fruit on which trace amounts of TDX residue are detected. In fact, however, the change will not allow more TDX on fruit than was allowed in the 1960’s, because ______.
(A) pre-1970 techniques for detecting TDX residue could detect it only when it was present on fruit in more than the trace amounts allowed by the new regulations
(B) many more people today than in the 1960’s habitually purchase and eat fruit without making an effort to clean residues off the fruit
(C) people today do not individually consume any more pieces of fruit, on average, than did the people in the 1960’s
(D) at least a small fraction of the fruit sold each year since the early 1960’s has had on it greater levels of TDX than the regulation allows
(E) the presence of TDX on fruit in greater than trace amounts has not been shown to cause any harm even to children who eat large amounts of fruit
The Complete the Argument type of question generally requires us to fill in an extra premise. The sentence that we have to complete almost always ends in the words ‘since’ or ‘because’, implying that we must find a
reason to strengthen or support the conclusion. This argument also has been left incomplete with a ‘because’ just before the blank.
Let us break up the argument.
Conclusion: The change will not allow more TDX on fruit than was allowed in the 1960’s.
The information provided is as follows:
• the pesticide TDX has been widely used by fruit growers since the early 1960’s
• but a regulation in force since 1960 has prohibited sale of fruit on which any TDX residue can be detected
• That regulation is about to be replaced by one that allows sale of fruit on which trace amounts of TDX residue are detected.
We understand from the information that the pesticide TDX has been used since the 1960’s but there has been a regulation in place that prohibits the sale of fruit on which any residue of the pesticide can be ‘
detected’.
The new regulation allows the sale of fruit on which
trace amounts of the residue of the pesticide are
detected.
One word to note here is ‘detected’. The other significant factor is the difference in the time between the two regulations. The conclusion is that the change will not allow any more TDX than the regulation in the 1960’s allowed. We are looking for the reason that conclusion is drawn. If the conclusion states that the change will not make a significant difference, it may be because there is not a great difference between the amount of TDX that could detected in the 1960’s and the trace amounts of TDX residue that can be detected now because the techniques for detection in the 1960’s were that effective, so they could detect the TDX down to the smallest amounts. Or it may be because the detection techniques were not that effective, so they could only detect quantities only down to a certain amount, which may be close to the trace amounts of residue.
Let us look at the options.
Options C and E are completely irrelevant. Option C discusses the individual consumption of fruit in the 1970’s and 1960’s; there is no information about the amount of TDX residue detected on fruit.
Option E discusses whether the amount of TDX residue on fruit is harmful to children or not. This option is also irrelevant since the argument doesn’t discuss whether the pesticide is harmful to any particular group of consumers and how harmful it is.
So, Options C and E can be eliminated.Option B is also irrelevant. The argument doesn’t discuss how people consume the fruit and the effect of TDX on them because of their consumption habits.
Therefore, Option B can also be eliminated.The argument is about the amount of TDX that can be detected. The argument states that any fruit that was detected to have more residue of TDX than allowed by the regulation could not be sold. So, all D tells us is that there was at least a small fraction of fruit that was not sold. It does not tell us the reason that the argument concludes that the change in regulation will not allow any more residue than was allowed since the 1960’s.
So, Option D also can be eliminated.Option A is the only one that discusses techniques for detection of TDX residue, which is what the argument is about. It states that the techniques for detection prior to the 1970's could only detect amounts that were more than the trace amounts allowed by the new regulation.
Therefore, A is the most appropriate option to complete the argument.Jayanthi Kumar.