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

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

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04 Jan 2012, 00:22
isn't D totally out of the context, it has to be B.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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14 Mar 2012, 06:03
I will pick C, because what level of pollutants is considered unhealthy in totally irrelevant to the variations og gases ?
Choice B is relevant because an accurate spectrometer may prove that any of the prior pollutant levels are not accurate (maybe more or less), and hence conclusions drawn on inaccuarate data are not reliable.
Choice D is relevant because any increase in the pollutant levels might have been resulted from companies exempted by the mayor from control measures.

Also, could you please indicate the source of the question?
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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14 Mar 2012, 22:57
B is the best choice

source as indicated in above posts: 1000 CR
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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25 Apr 2012, 07:02
Minheequang 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.

was very much confused with D and B....and still is
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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27 Apr 2012, 17:54
I choose D as well but was wondering if the broad scope of the time line in D gives B an edge.

Because he could have received a large donation in December, and then enact the bill in the next year. While the invention of a product does not mean that it was ever implemented, period.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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28 Apr 2012, 03:27
CR 1000 is not good for practice...
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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22 Jan 2013, 10:03
My reasoning went like this: what do I need to know in order to understand why the pollution apparently dropped?
It could have happened really and I need a a device to test it, or the pollution could have stopped being monitored appropriately.

Either way a new and more accurate device does not help me (B) because even if it is used, wich I am not sure of, and it is registering lower levels, I still do not know why the levels are lower.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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22 Jan 2013, 11:18
I agree with IanStewart and others: Bad question; don't study it. Choice (B) can help explain it: If a more accurate meter was invented, the city COULD have started using it at the end of 1988, and the old meter COULD have been overestimating, and then the more accurate readings of the new meter would explain the lower numbers in 1989. But (D) can also help explain it, depending on WHEN the mayor allowed the companies to be exempted. If that happened back in 1987, it would explain why pollution went up in spite of the regulations. On the other hand, if the mayor just recently allowed those exemptions, we would expect 1989 to suffer the effects of it. Since (D) doesn't tell us when the companies benefited from the exemption, it is not clear whether it helps to explain the discrepancies or not.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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24 Jan 2013, 14:45
Took me two minutes but B is correct. Tricky, Tricky, Tricky.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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14 Mar 2013, 05:41
still not quite convinced with B
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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14 Mar 2013, 08:41
I selected D but looks like the correct answer is B.

Logic: Newly invented Spectrometer does not bother the level of pollution in Los Diablos
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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17 Mar 2013, 20:29
Reason the answer is not D is : option says 1988 Industries were exempted which means those industries will create more pollution and that explains sudden high level of pollution ( 39 days in 1988) , so this helps in explaining and not the right answer

B tells that more accurate device was invented which means more number of days could be of smog alert in 1989 but thats not true so it doesn't help in explaining
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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20 Mar 2013, 02:46
Vercules wrote:
TheNona wrote:
still not quite convinced with B

Hi TheNona,

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.

The question asks us to find an answer choice that is LEAST helpful in explaining the pollution levels between 1986 and 1989. (B) may explain why the smog alerts decreased in 1989, but it will not explain the rise in pollution level in 1987 or 1988.

(D) on the other hand helps to explain the levels, because the Mayor "was found" to have accepted donations and exempted industries from pollution control measures. In 1988 it was found, so it is possible that he could have been taking donations in the past also; it could explain the pollution levels in 1987 and 1988. Thus, (D) explains.

Hope this helps,

Vercules

Vercules,
B) says that a new and accurate device was invented in 1989.
My questions are
1) did the city use it in 1989
2) whether old device that had been used was inaccurate?

I believe B) and D) are equally poised in the second level of usage.
1986 - 88 - Old device - inaccurate
89 - new device - accurate.

Can we debate on this ? Pl explain.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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22 Feb 2014, 04:51
B says about invention which does not imply to the question asked. So, B.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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28 Mar 2014, 08:18
IMO, D
What if the companies from which the mayor accepted dnations were not contributing significantly to the air pollution in the years before ? The companies were donating just out of goodwill and their donations helped curb the pollution ?
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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09 Apr 2014, 14:45
Minheequang 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.

The issue is between B & D
B- A new instrument was invented in1988-1. Does not imply it was put to use...This is not a strong excuse to justify B..It cannot be the basis for choosing an option..It can be considered for granted that the meter was put to use..Now,What if the more accurate spectrometer registered the pollution levels just below the red mark & hence the alert days were reduced in 1988

D-Exempting the industries for donations--- ..This is as good as it can be..--->Exemption-->More Pollution-->More days with smog alerts expected
-->But we have less days-->So it least helps in explaining the observation.
Vercules wrote:

The question asks us to find an answer choice that is LEAST helpful in explaining the pollution levels between 1986 and 1989. (B) may explain why the smog alerts decreased in 1989, but it will not explain the rise in pollution level in 1987 or 1988.

(D) on the other hand helps to explain the levels, because the Mayor "was found" to have accepted donations and exempted industries from pollution control measures. In 1988 it was found, so it is possible that he could have been taking donations in the past also; it could explain the pollution levels in 1987 and 1988. Thus, (D) explains.

Vercules

B- Rise in pollution levels was due to increase in pollution and the decrease was due to the reasons explained above....
Consider on a day in a year 1987 when the pollution level is at 701,which is greater than the red mark of 700.So we have an alert.
With the new meter the values were accurately found to be 699 and hence no smog alert..This could have happened on several occasions and so the decrease

D-Here when we assume that it is possible that Mayor took donations earlier too.We are assuming a premise outside the scope of the argument to be true.This is completely unacceptable & anyways to justify the trend we are further assuming that he took less donations in 1986,87 & 88 than in 89
-->Assumption over an assumption outside the scope of the argument

How can anyone ever have a doubt between B & D...
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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09 Apr 2014, 23:47
JusTLucK04 wrote:
Minheequang 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.

The issue is between B & D
B- A new instrument was invented in1988-1. Does not imply it was put to use...This is not a strong excuse to justify B..It cannot be the basis for choosing an option..It can be considered for granted that the meter was put to use..Now,What if the more accurate spectrometer registered the pollution levels just below the red mark & hence the alert days were reduced in 1988

D-Exempting the industries for donations--- ..This is as good as it can be..--->Exemption-->More Pollution-->More days with smog alerts expected
-->But we have less days-->So it least helps in explaining the observation.
Vercules wrote:

The question asks us to find an answer choice that is LEAST helpful in explaining the pollution levels between 1986 and 1989. (B) may explain why the smog alerts decreased in 1989, but it will not explain the rise in pollution level in 1987 or 1988.

(D) on the other hand helps to explain the levels, because the Mayor "was found" to have accepted donations and exempted industries from pollution control measures. In 1988 it was found, so it is possible that he could have been taking donations in the past also; it could explain the pollution levels in 1987 and 1988. Thus, (D) explains.

Vercules

B- Rise in pollution levels was due to increase in pollution and the decrease was due to the reasons explained above....
Consider on a day in a year 1987 when the pollution level is at 701,which is greater than the red mark of 700.So we have an alert.
With the new meter the values were accurately found to be 699 and hence no smog alert..This could have happened on several occasions and so the decrease

D-Here when we assume that it is possible that Mayor took donations earlier too.We are assuming a premise outside the scope of the argument to be true.This is completely unacceptable & anyways to justify the trend we are further assuming that he took less donations in 1986,87 & 88 than in 89
-->Assumption over an assumption outside the scope of the argument

How can anyone ever have a doubt between B & D...

Question is asking which option can help to LEAST explain this pattern.

1986-20days
1987-31
1988-39
1989-9

D says in 1988 mayor got donation and he exempted industries from those regulations... and we can see clearly in 1988 smoke alert increased..thus option D explains that why smoke alerts were highest in that year... we should not assume that mayor exempted them in 1989 as well. Option D is sufficient to tell us that observation in 1988 is ok.

B says new accurate spectrometer was developed in 1988... either it should increase the alerts or decrease the alerts... but we can not explain that 9 alerts were due to increased accuracy or any other reason. Thus I think option B LEAST explains the trend of number of alerts.
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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10 Apr 2014, 00:54
PiyushK wrote:
JusTLucK04 wrote:
Minheequang 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.

The issue is between B & D
B- A new instrument was invented in1988-1. Does not imply it was put to use...This is not a strong excuse to justify B..It cannot be the basis for choosing an option..It can be considered for granted that the meter was put to use..Now,What if the more accurate spectrometer registered the pollution levels just below the red mark & hence the alert days were reduced in 1988

D-Exempting the industries for donations--- ..This is as good as it can be..--->Exemption-->More Pollution-->More days with smog alerts expected
-->But we have less days-->So it least helps in explaining the observation.
Vercules wrote:

The question asks us to find an answer choice that is LEAST helpful in explaining the pollution levels between 1986 and 1989. (B) may explain why the smog alerts decreased in 1989, but it will not explain the rise in pollution level in 1987 or 1988.

(D) on the other hand helps to explain the levels, because the Mayor "was found" to have accepted donations and exempted industries from pollution control measures. In 1988 it was found, so it is possible that he could have been taking donations in the past also; it could explain the pollution levels in 1987 and 1988. Thus, (D) explains.

Vercules

B- Rise in pollution levels was due to increase in pollution and the decrease was due to the reasons explained above....
Consider on a day in a year 1987 when the pollution level is at 701,which is greater than the red mark of 700.So we have an alert.
With the new meter the values were accurately found to be 699 and hence no smog alert..This could have happened on several occasions and so the decrease

D-Here when we assume that it is possible that Mayor took donations earlier too.We are assuming a premise outside the scope of the argument to be true.This is completely unacceptable & anyways to justify the trend we are further assuming that he took less donations in 1986,87 & 88 than in 89
-->Assumption over an assumption outside the scope of the argument

How can anyone ever have a doubt between B & D...

Question is asking which option can help to LEAST explain this pattern.

1986-20days
1987-31
1988-39
1989-9

D says in 1988 mayor got donation and he exempted industries from those regulations... and we can see clearly in 1988 smoke alert increased..thus option D explains that why smoke alerts were highest in that year... we should not assume that mayor exempted them in 1989 as well. Option D is sufficient to tell us that observation in 1988 is ok.

B says new accurate spectrometer was developed in 1988... either it should increase the alerts or decrease the alerts... but we can not explain that 9 alerts were due to increased accuracy or any other reason. Thus I think option B LEAST explains the trend of number of alerts.

Agreed D explains the trend for 1988..But what about 87 and 89..So are you saying that we again assume the donations were valid for an year only
For B- If you go thru the example I suggested..you can easily explain the observation..at least far better than D..& it is always about the better one
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10 Apr 2014, 10:25
Minheequang wrote:
imanonymoususer wrote:
Minheequang 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.

A) Explains why number reduced on 1988
B) This does not. If more accurate then the numbers should have increased. -->From which info can you say that it will increase ? I can assume that because a new monitor machine is more accurate, it will prove less smog alert case which otherwise will prove positive. The initial problem in this case is that the control measures didn't work, but a new spectrometer helps solve the problem
C) Explains. Now new threshould is there, which maybe greater than the previous one.
D) Explains. Since companies exempted from air pollution measures, hence the decrease. --> I don't think so. A number of companies are exempted from controlled pollution measures, it means that such companies will pose more pollution. So why does the case of smog alert become fewer ? --> it strengthens the discrepancy
E) Since min 2 years required to break down the pollutants, hence the effects seen after 2 years..

IMO B

In D since companies were exempted from air pollution measures, their pollution level was high, once that in 1988 the mayor was found to accept the donations, the mayor had to stop maing these concesions with the companies and had to start measuring their pollution levels, hence, once measured the companies had to lower their pollution levels. => So D helps explain the drop in 1989
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Re: In 1986, the city of Los Diablos had 20 days on which air [#permalink]

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08 Jul 2014, 06:17
MKS wrote:
I recall this question and

The OA is B apparently, because even though the gas spectometer was invented, it doesn't mean it was used.

But I'm still sticking with D!

B is right

Firstly, Argument is asking about variation in pollution level from 86 to 89
and What measure do we have in argument - number of occurrences/ frequency of alert days on which air pollution reached unhealthful amounts and a smog alert was put into effect. (highlighted part is in the first line of arg.)

Secondly, What's wrong with D - if some industries are getting exemption "from air pollution control measures."
Then, surely frequency will be affected.

B is right just because of what 'bigfernhead' has mentioned about B.
Hope it helps !

Thanks a lot, It cleared my confusion.
Re: In 1986, the city of Los Diablos had 20 days on which air   [#permalink] 08 Jul 2014, 06:17

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