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Scientists have determined that Radon - a colorless, odorless, and tasteless gas - is unstable because of its

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by BTGmoderatorDC » Thu Jan 14, 2021 5:47 pm
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Scientists have determined that Radon - a colorless, odorless, and tasteless gas - is unstable because of its radioactive nature and continuously decays into Progeny. Since it has been proven that there was no Progeny at the time of earth’s formation, one can accurately estimate earth’s age by determining the increase in Progeny in earth’s atmosphere over the last 200 years and using it to determine how many years it would have taken to reach current levels of Progeny.

The answer to which of the following questions would be most important in determining whether using the method would help in achieving the stated objective?

A. Whether the rate of decay of Radon into Progeny is different during day time and night time?
B. Whether Progeny is stable or gets converted into some other gas at constant rate?
C. Whether there have been any changes in the atmosphere in the past century that have increased the radioactivity decay level of all gases?
D. Whether there are methods, better than the method given, to estimate the earth’s age?
E. Whether amount of Radon or Progeny varies from region to region?


OA C

Source: e-GMAT
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Source: — Critical Reasoning |

Assumption: The passage assumes that an average increase in the level of progeny gas can be used to determine the Earth's age over the last 200 years. It also assumes that the average increase of progeny in its lifetime would be the same as it increases 200 years ago.

Option A - Incorrect
The difference in the rate during the day or night doesn't necessarily impact the estimate of whether the rate of increase progeny gas is the same now or 200 years ago.

Option B - Incorrect
The main sentence measures the rate of increase of progeny in the atmosphere and not that of other gas. Therefore, this option doesn't validate the sentence given.

Option C - Correct
This option asks the question, whether there has been an increase in the radio active in the decay of gas 200 years ago, and if it can be used to estimate the Earth's age which is what we need to base the assumption on.

Option D - Incorrect
It is irrelevant to the question as we are required to use the method stated against the stated assumption.

Option E - Incorrect
Since the main sentence is talking about the Earth's atmosphere as a whole, calculating the variance region by region doesn't affect the assumption stated.
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It was interesting. Thank you
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