In 1986, the city of Los Diablos had 20 days on which air : GMAT Critical Reasoning (CR)
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# In 1986, the city of Los Diablos had 20 days on which air

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In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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26 May 2010, 04:06
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In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.
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Re: City of Los Diablos [#permalink]

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26 May 2010, 06:39
it should be D
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Re: City of Los Diablos [#permalink]

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26 May 2010, 08:20
D
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Re: City of Los Diablos [#permalink]

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26 May 2010, 08:28
Another vote for D. Though, E is a close competitor
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Re: City of Los Diablos [#permalink]

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26 May 2010, 11:14
dimitri92 wrote:
Another vote for D. Though, E is a close competitor

I actually thought that E, if true, would be one of the most eloquent explanations, so I wouldn't have considered E at all.
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Re: City of Los Diablos [#permalink]

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26 May 2010, 19:55
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I vouch for B, a new gas spectrometer might have been invented in 1988, but how can we assume it served any purpose or was actually used.
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Re: City of Los Diablos [#permalink]

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26 May 2010, 21:01
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The answer is B. The reason it is the answer is because it says the new system was more accurate. Being more accurate doesn't mean that the old results are not true, it only means that they are now more certain about the levels. It does the least to tells us that that what is in the passage is true, because with B we're not certain whether the new gas spectrometer helped or made worse the evidence in the passage.

E helps because it tells us why in 1989 we started to see such a drastic drop.

D helps because it would give a good reason why the drop in incidences began.

I hope this helps.

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Re: City of Los Diablos [#permalink]

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27 May 2010, 06:55
sk818020 wrote:
The answer is B. The reason it is the answer is because it says the new system was more accurate. Being more accurate doesn't mean that the old results are not true, it only means that they are now more certain about the levels. It does the least to tells us that that what is in the passage is true, because with B we're not certain whether the new gas spectrometer helped or made worse the evidence in the passage.

E helps because it tells us why in 1989 we started to see such a drastic drop.

D helps because it would give a good reason why the drop in incidences began.

I hope this helps.

Jared

I didnt find the explanation satisfactory. "it says the new system was more accurate. Being more accurate doesn't mean that the old results are not true, it only means that they are now more certain about the levels. "

Where is it stated that they are more certain less certain about the levels because of the new system, thats an assumption just as

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.

Option A) you could argue that in 1987 they enacted the law and thats why the level decreased. So it explains lets assume

Option B) they installed new system, so the new system shows a new reading, which should be true we cant say that it might be true or not, if we go that way then we can argue old system might have been faulty or not, but i mean i am not satisfied how this is the least helpful.

(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.

After revising they corrected the levels decreased according to new scale. So it helps.

I am trying to understand, no hard feelings.
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Re: City of Los Diablos [#permalink]

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27 May 2010, 08:06
BlueRobin wrote:
Where is it stated that they are more certain less certain about the levels because of the new system, thats an assumption just as

B states; In December of 1988 a new and far more accurate gas spectrometer was invented. The question stem says that we must assume this is true. I'm using certainty and accuracy as synonyms. The more accurate the results are the more certain you can be of those results. How could something be more accurate and not more certain. Regardless, the point is that in this particular question we are looking for the answer that is least helpful in explaining the air pollution levels. In order for B to be helpful there would have to be other information involved; for example;

1. They could actually use this gas spectrometer.
2. More accurate results would lead cause the number of smog alerts to increase and not decrease.
3. It wouldn't take a ridiculous amount of time to determine the results of the info gather by the new technology.

I could come up with more examples, but you get the picture. In order for B to be helpful we would need additional information, which is not provided in the passage.

Again I'll go through why the other choices are helpful.

A. They didn't put the laws into affect until the end of 1988, which would be a good reason why the level did not drop until 1989.
C. In 1989 they came up with a new scale which could be a good reason why the number started dropping so drastically. The new scale was less sensitive to smog levels.
D. Would be a good reason why the number of days dropped because it shows the drop is not do to decreased smog level but instead is due to the inspectors taking less readings.
E. This would be a good reason because it would mean that measures enacted in 1987 did not have an impact until 1989.

Hope this helps.

What is the OA?

Thanks,

Jared
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Re: City of Los Diablos [#permalink]

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28 May 2010, 04:38
Official Ans is B

Quote:
B states; In December of 1988 a new and far more accurate gas spectrometer was invented. The question stem says that we must assume this is true. I'm using certainty and accuracy as synonyms. The more accurate the results are the more certain you can be of those results. How could something be more accurate and not more certain. Regardless, the point is that in this particular question we are looking for the answer that is least helpful in explaining the air pollution levels. In order for B to be helpful there would have to be other information involved; for example;

1. They could actually use this gas spectrometer.
2. More accurate results would lead cause the number of smog alerts to increase and not decrease.
3. It wouldn't take a ridiculous amount of time to determine the results of the info gather by the new technology.

I am confused with one thing, why cant you assume that the old meter was probably showing the wrong results i.e. increased readings than actual levels, and with the installation of the new meter they started reading correct results, so its was helpful in reading the reduced readings.
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Re: City of Los Diablos [#permalink]

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01 Jun 2010, 07:18
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Regarding D,

Doesn't it go against the given information? In '89, the smog # went down. However, if the mayor exempted companies from pollution control, there would be MORE pollution, and hence MORE smog #.

Therefore, it doesn't help in explaining why the number went down.

Why is this thinking wrong?
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Re: City of Los Diablos [#permalink]

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01 Jun 2010, 07:33
Quote:
why cant you assume that the old meter was probably showing the wrong results

The reason you can't assume this is because the passage doesn't give us any information indicating this is a safe assumption. Again, we are basing our reasoning only on what is in the passage, regardless of what would seem to be the case in the real world or based on common sense.

The passage only states that the pollutants were monitored by a gas spectrometer. It does not say that a new gas spectrometer will cause there to be more or less alert days. It could cause more, it could cause less. Based on the passage we don't know.

Thanks,

Jared
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Re: City of Los Diablos [#permalink]

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01 Jun 2010, 07:38
hmm....

I narrowed down between A and B but was not sure how to interpret, "more accurate gas spectrometer".
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Re: City of Los Diablos [#permalink]

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01 Jun 2010, 11:46
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its B.

its not D because D says

In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.

Now how does one know that the pollution was because of industries and not because of say a large amount of cars on the road.
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Re: City of Los Diablos [#permalink]

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29 Aug 2012, 09:37
sk818020 wrote:
Quote:
why cant you assume that the old meter was probably showing the wrong results

The reason you can't assume this is because the passage doesn't give us any information indicating this is a safe assumption. Again, we are basing our reasoning only on what is in the passage, regardless of what would seem to be the case in the real world or based on common sense.

The passage only states that the pollutants were monitored by a gas spectrometer. It does not say that a new gas spectrometer will cause there to be more or less alert days. It could cause more, it could cause less. Based on the passage we don't know.

Thanks,

Jared

Hi guys,

Thanks for the explanation above.

But just to add, I feel B states that new instrument was INVENTED, as per the question we must believe it was invented but we can not assume that the same instrument was installed or used.

Hope my reasoning is right.

Thanks,
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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29 Aug 2012, 10:22
spectrometer is nowhere mentioned in the argument
so replacing it with any other instrument is same
correct me if i am wrong

i mean what does a time machine got to do with increase or decrease in pollution
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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18 Nov 2012, 21:28
i will go with option 'b' ,inventing an equipment does not mean helpful in explaining pollution levels.
coming to 'd'-if industries are exempted from pollution laws,it will effect the pollution levels.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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18 Nov 2012, 21:32
i will go with option 'b' ,inventing an equipment does not mean helpful in explaining pollution levels.
coming to 'd'-if industries are exempted from pollution laws,it will effect the pollution levels.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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19 Nov 2012, 01:38
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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24 May 2013, 06:11
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BlueRobin wrote:
In 1986, the city of Los Diablos had 20 days on which air pollution reached unhealthful amounts and a smog alert was put into effect. In early 1987, new air pollution control measures were enacted, but the city had smog alerts on 31 days that year and on 39 days the following year. In 1989, however, the number of smog alerts in Los Diablos dropped to sixteen. The main air pollutants in Los Diablos are ozone and carbon monoxide, and since 1986 the levels of both have been monitored by gas spectrography.
Which of the following statements, assuming that each is true, would be LEAST helpful in explaining the air pollution levels in Los Diablos between 1986 and 1989?

(A) The 1987 air pollution control measures enacted in Los Diablos were put into effect in November of 1988.
(B) In December of 1988 a new and far more accurate gas spectrometer was invented.
(C) In February of 1989, the Pollution Control Board of Los Diablos revised the scale used to determine the amount of air pollution considered unhealthful.
(D) In 1988 the mayor of Los Diablos was found to have accepted large campaign donations from local industries and to have exempted those same industries from air pollution control measures.
(E) Excess ozone and carbon monoxide require a minimum of two years to break down naturally in the atmosphere above a given area.

My initial pick was D too. But I guess after reading it the second time , I see why B makes sense.

Quote:
(B) In December of 1988 a new and far more accurate gas spectrometer was invented..

As other people have pointed out , it only says spectrometer was invented . No mention of it being used to monitor the levels.

Quote:
(D) In 1988 the mayor of Los Diablos was found to have acceptedlarge campaign donations from local industries and to have exempted those same industries from air pollution control measures. .

No doubt , the pollution increases , if mayor exempts those industries from air pollution measures. So accepting donations to exempt those industries , meant increase in air pollution. If we focus on the bold part above in D , it says in 1988 , the mayor was found to have accepted. It doesn't say that mayor ACCEPTED in 1988 and EXEMPTED the industries IN 1988. He was FOUND to have accepted in 1988. He might have accepted the donations before 1988 or in the middle of 1998 or end of 1988.They just found that thing in 1988. The exemption might have happened in 1987. Or if they found out by the end of 1988 , then exemption might have happened till they found out , in 1988. This kinda explains why the pollution increased till 1988. And mebbe once they found out in 1988 , what mayor had done , they might have reverted the exemptions , which is why in 1989 pollution went down . I know it is bit of a stretch to make these assumptions , but when we are to choose between B and D (In B - where you make an assumption that invented meant used + cant justify yet as to why did new and accurate instruments show lower pollution levels) , the assumptions what we made in D seems safer.

HTH
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Re: In 1986, the city of Los Diablos had 20 days on which air   [#permalink] 24 May 2013, 06:11

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