Last year Comfort Airlines had twice as many delayed flights as the

Passage analysis
Last year Comfort Airlines had twice as many delayed flights as the year before,
Last year, Comfort Airlines had many delayed flights
Last year, the number of flights delayed was double the number of flights delayed the year before that.
but the number of complaints from passengers about delayed flights went up three times.
Passengers complained about these delayed flights.
Last year the number of complaints were three times the number in the year before last.

We can infer that though the number of flights delayed doubled last year, the number of complaints about delayed flights tripled disproportionately.

It is unlikely that this disproportionate increase in complaints was rooted in an increase in overall dissatisfaction with the service Comfort Airlines provides, since the airline made a special effort to improve other aspects of its service last year.
This disproportionate increase in complaints was not because of an increase in overall dissatisfaction with the service of Comfort Airlines
because Comfort Airlines put in special effort to improve the other areas of its service last year.
Conclusion
Overall dissatisfaction with the service provided by Comfort Airlines is unlikely to be the reason behind the disproportionate increase in complaints by the passengers.



Pre-thinking
Strengthen Framework
Now per our understanding of the passage, let’s first write down the strengthen framework:

What new information will help us believe more in the conclusion
Overall dissatisfaction with the service provided by Comfort Airlines is unlikely to be the reason behind the disproportionate increase in complaints by the passengers.


Given that
Last year, the number of delayed fights of CA was double the number of delayed flights the year before.
But the number of complaints last year was three time the number of complaints the year before.
CA made special improvements to the other aspects of its service last year.


Thought process


If the number of flights delayed doubled, then one would expect the complaints also to more or less double.

In this case, the assumption made would be that the number of total passengers of CA had not been higher last year than the year before (that is the number of passengers had either remained the same or reduced somewhat).



But the number of complaints has unexpectedly risen by three times.



This in spite of the fact that CA made specially improved the other aspects of its service(other than the delay aspect).



So, CA is confident that the unexpected increase in the number of complaints is not because of

The other aspects of the service (they have taken care of that last year itself)
The usual number of delays (had it been because of the number of delays, then the number of complaints was expected to go up accordingly with the increase in the number of flights delayed - twice - and not go up three times).


Then what has led to the disproportionate increase in complaints?

Strengthener

Clearly, there is something else that the passengers are complaining about. Any statement/evidence indicating a factor/reason that could have caused the disproportionate increase will strengthen the airline’ conclusion that the complaints are not because of overall dissatisfaction with their services.

Answer Choices
Option A

The passage mentions “the numbers of delayed flights” quite explicitly. Thus the total number of flights does not matter at all to the discussion.

Thus, this is not the correct choice.

Option B

The reason why the flights had been delayed does not matter. We need to find the reason behind the disproportionately increased number of complaints. Therefore, this is irrelevant to the discussion.

Thus, this is not the correct answer choice.

Option C

Why the improvements were made is not important as long as they were made and therefore the disproportionate increase in complaints could not have been related to the service aspect of the airlines. This option does not give any alternative reason behind the increased number of complaints.

Thus, this is not the correct choice.

Option D

This option introduces a factor about the delays that has not been considered in the argument. The argument only looks at the number of delays and the number of complaints.

What about the kind of delay itself?

This option says the delays were lengthier on average and this could have led more than the expected number of passengers to complain about them.

This is in line with pre-thinking.

Thus, this is the correct answer choice.

Option E

The option implies that the average number of passengers per flight was either the same or less than the year before last. This further confuses us. It still does not give the reason why the number of complaints increased threefold if the average number of passengers did not increase.

Thus, this is not the correct answer choice.

D for me

a- out of scope
c-irrelevant
e-out of scope
b- if delay due to weather, passenger should not complaint, because it was not airlines fault.

d- if length of delays were increased, passengers will complaint, even though the same passengers did not complaint to that extant when these flights were delayed for shorter span of time.

I am still not clear why A is incorrect.
I was confused between A and D and ended up choosing A.

For me both A and D needs to assume something to explain the disproportion.

By saying “It is unlikely that this disproportionate increase in complaints was rooted in an increase in overall dissatisfaction with the service Comfort Airlines provides, since the airline made a special effort to improve other aspects of its service last year,” the argument is set up to make clear that the complaints are triggered by delays.

So we are faced with an unexplained disproportion. The number of delays doubled, but the number of complaints about delays tripled.

(A) Comfort Airlines had more flights last year than the year before.

This choice is tempting because if Comfort Airlines had more flights, then likely Comfort Airlines had more customers. If the same proportion of customers were to complain while the total number of customers increased, then we would have more complaints.

So, if you were looking for a reason for a general increase in complaints, this answer choice might provide that reason.

We are not, however, looking for a reason for a general increase in complaints. The prompt has already stated as fact that the number of delayed flights doubled. It would logically follow that a doubling in delayed flights would result in a doubling in complaints, NO MATTER HOW MANY FLIGHTS IN TOTAL COMFORT AIRLINES HAD LAST YEAR. Only the delayed flights should trigger complaints about delays.

So, this choice does nothing to explain why the complaints about delays would increase more than delays did.

(B) Last year, a single period of unusually bad weather caused a large number of flights to be delayed.

This choice indicates that there was likely a concentration of delays in one time period. A test-taker might construe that concentration as being the cause of the increase in complaints per delay.

It is not, however, clear that such a concentration of delayed flights would cause people to be more likely to complain about delays. Further, one could argue that people who are aware that weather caused the delays would not complain about the delays.

So, this choice does not explain why complaints increased more than delays increased.

(C) Some of the improvements that Comfort Airlines made in its service were required by new government regulations.

While it is possible that a test-taker could interpret this answer choice to mean that Comfort Airlines only takes care of customers because of government involvement and thus has a poor customer service culture, the truth is that this answer choice does not indicate any change from one year to the next year in the attitude of Comfort Airlines toward customers, and therefore it does not explain why there would be a year to year change in the number of complaints.

Further, without additional information, it is close to impossible to reasonably argue that service improvements as a result of government regulation would result in increased complaints about delays. Service improvements should result in a decrease, rather than an increase, in complaints.

(D) The average length of flight delay was greater last year than it was the year before.

Correctly answering GMAT Critical Reasoning questions often requires using some common sense. So, let’s use some here.

It makes sense that the longer a delay, the more likely it is that people will complain about that delay. So, if the number of delays doubles AND the delays are longer, then likely the number of complaints will more than double.

Therefore, this is the answer that explains the disproportionate increase in complaints. Delays doubled, but the delays triggered more than twice as many complaints because the delays were longer.

(E) The average number of passengers per flight was no higher last year than the year before.

What this choice says actually RULES OUT a possible reason for the increase in complaints. If the number of passengers per flight had increased, then that increase could explain why there were more complaints per delay. Had there been more passengers per flight, then when delays doubled, more that twice as many passengers would have experienced those delays. So, in saying that the number of passengers per flight stayed the same, this choice rules out one possible reason for the increase in complaints.

To avoid choosing a choice like this one, which is relevant to the argument but does not answer the question, you have keep clear in your mind exactly what the question is asking you to find.

Therefore, the correct answer is

Option A. If the number of flights increase, with twice the number of delays, the number of complaints can also increase disproportionately. Let me know if this explanation is ok

We are not looking for a reason for a general increase in complaints. The prompt has already stated as fact that the number of delayed flights doubled. It would logically follow that a doubling in delayed flights would result in a doubling in complaints, NO MATTER HOW MANY FLIGHTS IN TOTAL COMFORT AIRLINES HAD LAST YEAR. Only the delayed flights should trigger complaints about delays.

So, this choice does nothing to explain why the complaints about delays would increase more than delays did.

This is a paradox question.

So, our first task is to identify the paradox (i.e., contradictory premises).

The paradox is that the number of complaints TRIPLED even though the number of delayed flights only DOUBLED.
All things considered equal, the number of complaints should have DOUBLED (not tripled).

So, we're looking for an answer choice that resolves this mystery.

Can you think of something that might explain the paradox? If so, then look for that explanation among the answer choices.
If you can't think of something, check each answer choice, and as you do so, keep reminding yourself of the paradox (complaints tripled even though delays only doubled)

(A) Comfort Airlines had more flight last year than the year before.
Does this explain why the number of complaints TRIPLED even though the number of delayed flights only DOUBLED?
No, it doesn't resolve the paradox.
ELIMINATE A

(B) Last year a single period usually bad weather caused a large number of flights to be delayed.
Does this explain why the number of complaints TRIPLED even though the number of delayed flights only DOUBLED?
No.
ELIMINATE B

(C) Some of the improvements that Comfort Airlines made in its service were required by new government regulations.
Does this explain why the number of complaints TRIPLED even though the number of delayed flights only DOUBLED?
No.
ELIMINATE C

(D) The average length of flight delay was greater last year than it was the year before.
Does this explain why the number of complaints TRIPLED even though the number of delayed flights only DOUBLED?
YES!!!
There were twice as many delays last year AND those delays were WORSE than the year before. So, there was even more to complain about!
That explains everything!
KEEP D

(E) The average number of passengers per flight was no higher last year than the year before.
Does this explain why the number of complaints TRIPLED even though the number of delayed flights only DOUBLED?
No.
ELIMINATE E

Answer: D

Cheers,
Brent

Hi GMATNinja GMATGuruNY - if my understanding is correct, D is correct because the Ratio of number of complaints / 1 delayed flight will increase in option D

However, in option B - if many flights are delayed ALL at the same time because of the weather - would the Ratio of the number of complaints / 1 delayed flight INCREASE OR stay the same ?

I thought the ratio of number of complaints/ 1 delayed flight WILL INCREASE because the flights are delayed "ALL AT THE SAME TIME". Because everyone's flight is delayed at the same time (i.e. many passagers connecting fights will be missed), the number of complaints / 1 delayed flight SHOULD be higher.

Thats why I selected B

jabhatta2, Not an expert, but see if this helps

Option D - This option explains why the the complaints increase at a higher rate than the delays. If the delay is for 10-15 minutes, it'd still count as a delay but most of the passengers might not even realise it, let alone complain about it. However, if the length of delay is 2-3 hours, then probably everybody would complain about it, essentially increasing the number of complaints per flight (like you've pointed out)

Option B - If a large number of flights were delayed because of unusual weather, the passengers probably wouldn't complain about that delay. The airline literally cannot do anything about the weather. As such, I'd not expect the disparity/paradox given in the question. This option just adds more confusion to the stem.

GMATNinja GMATGuruNY - thoughts ?

You're right about (D) -- imagine you are a passenger, and your flight gets delayed 10 minutes. Are you likely to bother with filling out a formal complaint?

Now, say that your flight is delayed 5 hours. You'd be much more likely to fill out a complaint for the longer delay, because it is simply more of a headache to be delayed for a longer period of time. So, longer delays can account for the above-expected number of complaints.

That's why (D) is the correct answer.

As for (B), your analysis makes a leap too far. All (B) tells us is that many delays happened during a single period of bad weather. We have no idea how many passengers even needed connecting flights, or whether the concentration of delays in the same time period impacted connections differently than more spread-out delays would have done.

So, (B) doesn't really give us a strong reason for why complaints are up so much. The question asks which answer choice "most helps" to explain the increase in complaints, and (D) is the clear winner.

I hope that helps!

Why A is incorrect:

There is a clear correlation between the number of delayed flights and the number of complaints about “delayed flights” (We expect the correlation to be directly proportional). However, we can’t figure any correlation between the number of total flights and the number of complaints about “delayed flights”.

Posted from my mobile device

Year Before = n, Last Year = 2n
Year Before = c, Last Year 3c

n = number of flights
c= number of complaints