confused answer for " dissolved salt" why not E?

[CrystalSpringston]

Hi experts,

I have 2 questions .

1) What A is saying is the rate of salts flowing into ocean in recent hundreds of years should be the same as the whole period, namely from the very first beginning when the salt level is 0 to now.
As a result , we can calculate the age of ocean by the rate.

If I interpret it correctly, then my question is: A actually repeats the first sencent of the question:The Earth's rivers constantly carry dissolved salts into its oceans.
In other words, the OA is a premise already stated . But for such assumption questions, we cannot choose an existed premise as the correct answer.

Pls help to correct me if I am wrong somewhere.

2) I need your confirmation on my understanding that why E is incorrect.
E says None of the salts carried into the Earth's oceans by rivers are used up by biological activity in the oceans.
It is too extreme to state it. If the amount of being using up is big, I think it make sense to affect the calculation. But If there is only trace amount, we can ignore it.
So E is not alway true.

Thank you!

[RonPurewal]

Hi experts,

I have 2 questions .

1) What A is saying is the rate of salts flowing into ocean in recent hundreds of years should be the same as the whole period, namely from the very first beginning when the salt level is 0 to now.
As a result , we can calculate the age of ocean by the rate.

If I interpret it correctly, then my question is: A actually repeats the first sencent of the question:The Earth's rivers constantly carry dissolved salts into its oceans.
In other words, the OA is a premise already stated . But for such assumption questions, we cannot choose an existed premise as the correct answer.

Pls help to correct me if I am wrong somewhere.

ah, ok, i see what's happening here.

'constantly' does NOT mean 'at a constant rate'.
rather, 'constantly' just means 'without stopping'. (it's the same as 'continually'.)

note, by the way—
on an assumption question, the wrong answers will NEVER repeat existing statements.
this will never happen. never ever ever.
if you think this is happening, then you are definitely misinterpreting something—and you should go back and figure out exactly what that might be.

[RonPurewal]

2) I need your confirmation on my understanding that why E is incorrect.
E says None of the salts carried into the Earth's oceans by rivers are used up by biological activity in the oceans.
It is too extreme to state it. If the amount of being using up is big, I think it make sense to affect the calculation. But If there is only trace amount, we can ignore it.
So E is not alway true.

Thank you!

nope. this is all irrelevant.

it makes no difference whether (or to what extent) salts 'are used up by biological activity',

here, the evidence involves the OVERALL rate of increase in salt levels. this rate accounts for everything that affects salt levels in any way at all.
if ocean animals are using salt for whatever biological purpose, that is already factored into the levels that are measured.

[RonPurewal]

analogy:
Cindy has a high-paying job. When she started this job, she had no savings.
Over the past year, she has been able to save $1,000 per month. She now has $60,000 in savings, so she must have been hired at this job 5 years (= 60 months) ago.

this should make the issue obvious:
$1,000/month is only what cindy has saved over the past year.
we're just assuming—for no good reason—that we can extrapolate the same rate of saving all the way back to whenever cindy was hired.

[RonPurewal]

in the analogy above, choice A is like
Cindy did not receive a large pay raise just over a year ago.
again, it should be quite clear why this is necessary. (if you negate it—if she DID get a large raise just over a year ago—then $1000/month is probably much more than she was able to save before.)

choice E, on the other hand, is ilke
Cindy does not have to use any of her salary to pay down old student loans.
it should be equally clear why this is irrelevant: the figure of $1000/month is what cindy is able to save after taking all of her expenses into account.
so, it really doesn't matter what those expenses are, as long as they are reasonably consistent.

[RichaChampion]

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

Ron Sir,

I have a question. Although our job in Verbal is always to find the least devil, but Option A is also not 100% air tight.

First Let me summarize How I tackled the question -
B. Out Of Scope.

In one perspective option C and E are alike. I have a reason to say this.
salts that leach into the Earth's oceans directly from the ocean floor - This is a activity whose time frame is not mentioned that means it is common since beginning of earths existence, hence it effect is common throughout and thus nullified.

Same goes with option E -
None of the salts carried into the Earth's oceans by rivers are used up by biological activity in the oceans

This is common throughout.

D is absolutely a Nonsense.

So by the process of elimination we are left with A.

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

Past 100 years is a very small time frame if we consider the oceans age.
Also Unusually high will not be exponentially high than the remaining years of years and in the comparison of those years 100 years is almost a negligible quantity and thus "unusually large during the past hundred years. " is also almost a negligible quantity.


The age of earth is estimate to be 4.54 × 10^9. Thus 100 years are nothing.
Lets suppose every year XKG salts come into ocean. Now what will be unusually high for 100 years 3 times, 4 times.
unusually high doesn't means impossible high as high as it covers 1 Billion years salt deposit. If we look at this aspect A is also not an air tight Option though it is the least devil among 5 choices.

[RonPurewal]

you are seriously over-thinking this. obviously, the GMAT is not going to expect test takers to know the approximate age of the earth (not to mention that the whole point of the problem is that earth's age is unknown!).

the "100 years" in choice A is significant because, according to the passage, the salt levels have been measured for the last 100 years.

so, no, that's NOT "negligible"!
if the deposits have been unusually big for the last 100 years, then ALL of the measurements will be non-representative!