Earth age

[ssgmatter]

The Earth's rivers constantly carry dissolved salts into its oceans. Clearly, therefore, by taking the resulting increase in salt levels in the oceans over the past hundred years and then determining how many centuries of such increases it would have taken the oceans to reach current salt levels from a hypothetical initial salt-free state, the maximum age of the Earth's oceans can be accurately estimated.

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

A. The quantities of dissolved salts deposited by rivers in the Earth's oceans have not been unusually large during the past hundred years.

B. At any given time, all the Earth's rivers have about the same salt levels.

C. There are salts that leach into the Earth's oceans directly from the ocean floor.

D. There is no method superior to that based on salt levels for estimating the maximum age of the Earth's oceans.

E. None of the salts carried into the Earth's oceans by rivers are used up by biological activity in the oceans

I chose E which makes the most sense because it has to be assumed that the salt level is not used for any other purpose so as to measure the age of the Earth

Am I correct??..

Please share your thoughts guys

Thanks!

[asamaverick]

IMO it should be A.

The ability to correctly measure earth's age will depend on a consistent (or a gradually rising) level of the salt that is deposited. If the quantities of salt deposited has been unusually large during the past 100 years, it will not be possible to calculate the age using this method.

E does make sense and if not for A it would have been my choice. But if we try to stay within the context then A is the best answer. Also, it is possible to break E. Consider that the salts deposited into ocean are used up by biological activity, but what if it were possible to measure the salt loss because of that biological activity. If so E need not be the assumption on which the argument depends.

What is the OA?

[ssgmatter]

IMO it should be A.

The ability to correctly measure earth's age will depend on a consistent (or a gradually rising) level of the salt that is deposited. If the quantities of salt deposited has been unusually large during the past 100 years, it will not be possible to calculate the age using this method.

E does make sense and if not for A it would have been my choice. But if we try to stay within the context then A is the best answer. Also, it is possible to break E. Consider that the salts deposited into ocean are used up by biological activity, but what if it were possible to measure the salt loss because of that biological activity. If so E need not be the assumption on which the argument depends.

What is the OA?

Thankyou for your thoughts....I think I am more confused now....

I will still stick to E here......Any further explanations for E and A here

I will post the OA as the this thread progress with more discussions..

Thanks!

[thephoenix]

if D is not the ans then i wud like to understand the reason for eliminating it

pls quote the source also!!!!!!!

[ssgmatter]

if D is not the ans then i wud like to understand the reason for eliminating it

pls quote the source also!!!!!!!

I dont know if this makes any sense but somehow I feel D is too extreme.....Any thoughts???

[kevincanspain]

How about an analogy? The balance is Phil's bank account is currently $50,000, $1000 higher than it was three months ago and $2000 higher than it was 6 months ago. Thus it is likely Phil opened this bank account more than 10 years ago.

[ssgmatter]

How about an analogy? The balance is Phil's bank account is currently $50,000, $1000 higher than it was three months ago and $2000 higher than it was 6 months ago. Thus it is likely Phil opened this bank account more than 10 years ago.

I can understand the analogy but somehow not able to relate this to the argument and the question at hand....Please elaborate more on this..

I am somehow not able to internalize the argument....language seems to be too convoluted....

[kevincanspain]

Compare the balance in your bank account to the salt levels in the oceans.

Why can't we say that you opened your account over 10 years ago?

[thephoenix]

pls post the oa

[ssgmatter]

pls post the oa

OA is A

[kevincanspain]

The argument claims that by examining a time sample of the last one hundred years, we can estimate the age of the oceans. Yet how do we know that the last 100 years were representative of the history of the earth in terms of salt deposits in the oceans? Likewise, how do we know that the transactions in your bank account in the past 6 months are representative of the past decade?

[ssgmatter]

The argument claims that by examining a time sample of the last one hundred years, we can estimate the age of the oceans. Yet how do we know that the last 100 years were representative of the history of the earth in terms of salt deposits in the oceans? Likewise, how do we know that the transactions in your bank account in the past 6 months are representative of the past decade?

So here A does the logic gap filling.....A. The quantities of dissolved salts deposited by rivers in the Earth's oceans have not been unusually large during the past hundred years.

Am I correct Kevin?....Please advise

[ansumania]

The argument claims that by examining a time sample of the last one hundred years, we can estimate the age of the oceans. Yet how do we know that the last 100 years were representative of the history of the earth in terms of salt deposits in the oceans? Likewise, how do we know that the transactions in your bank account in the past 6 months are representative of the past decade?

kevin,

this explanation makes sense. However, how would we get rid of option D?

will removing some salt in some of the years not hamper the estimation of the age?

pl. explain....

[sk818020]

this explanation makes sense. However, how would we get rid of option D?

will removing some salt in some of the years not hamper the estimation of the age?

pl. explain....

D is not the answer because D says that there is no superior method of determining the age of earth's oceans, but the passage doesn't say whether the sea salt method is good or bad as an indicator of the age of earth's ocean. It only says that this is a method of determining the age of Earth's oceans. The passage doesn't qualify whether this method is good or bad.

[ansumania]

this explanation makes sense. However, how would we get rid of option D?

will removing some salt in some of the years not hamper the estimation of the age?

pl. explain....

D is not the answer because D says that there is no superior method of determining the age of earth's oceans, but the passage doesn't say whether the sea salt method is good or bad as an indicator of the age of earth's ocean. It only says that this is a method of determining the age of Earth's oceans. The passage doesn't qualify whether this method is good or bad.

oops ..my bad...I wanted to know why E can't be correct. .......