I go with option A.

The author assumes that a primary cause for the heightened delays is the lack of unoccupied landing and takeoff slots for commercial airlines. Thus, the author argues that the best method is to increase the number of slots. However, option A gives a different reason for the delays. If it is attributed to something other than the number of slots, increasing them would not necessarily help.

I would say (A) is the strongest.

The argument makes an unspoken assumption that delays are caused by the lack of allocated takeoff/landing slots. (A) suggests entirely different causes (weather & lack of airport equipment) of the problem, which won't change regardless of how many slots are allocated to airlines.

OA is A. But is there any difference between the term " nation's increasingly busy airports" used in argument and term " nation's busiest airports" used in correct option?

I understand that other options can easily be eliminated, but if we have option F : The major causes of delays at the nation's increasingly busy airports are bad weather and overtaxed air traffic control equipment.

What would be the answer A or F? Are we required to figure out such subtle differences in GMAT ?

Thanks

Hi CARK,

No, you will not need to figure out such difference in GMAT. Even in the current question, you are not supposed to figure out such difference. If you read the passage carefully, the conclusion talks about "busiest airports", the same as that in the correct option statement. Since our job is to weaken the conclusion, option A clearly does that by referring to "busiest airports".

As you can now think, if there were option F as you wrote, it would not be correct since it talks about "increasingly busy airports" whereas the conclusion talks about "busiest airports".

Remember in all argument questions (strengthen, weaken, evaluate, flaw), you need to have a RAZOR SHARP FOCUS on the CONCLUSION. Whatever premises say, if the conclusion is any different, then you need to pay attention to the conclusion.

Does it help?

Thanks,
Chiranjeev
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Plan assumes that lack of enough slots causing the delay. Then i will attack this causal assumption by providing that something else is causing the delay.
Clearly A mention that it's the bad weather , not the lack of slots, is causing the problem.


(A) The major causes of delays at the nation's busiest airports are bad weather and overtaxed air traffic control equipment. Correct
(B) Since airline deregulation began, the number of airplanes in operation has increased by 25 percent. this says, situation is aggravated and hence doesn't attack
(C) Over 60 percent of the takeoff and landing slots at the nation's busiest airports are reserved for commercial airlines. Adding extra slots don't help
(D) After a small mid western airport doubled its allocation of takeoff and landing slots, the number of delays that were reported decreased by 50 percent. Strengthen
(E) Since deregulation the average length of delay at the nation's busiest airports has doubled. restating the premise.

Explanation choice A

Type: weaken

Conclusion: More slots allocated to commercial airlines => reduce the delays

Assumption: shortage of slots allocated to commercial airlines is the main reason for the delay

Break the assumption: hence choice A is correct

Since the deregulation of airlines, delays at the nation's increasingly busy airports have increased by 25 percent. To combat this problem, more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines.

Type - Weaken
Boil it down - To reduce delays , more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines.
Pre-Thinking - Some alternate cause that is not affected by allocation of slots

(A) The major causes of delays at the nation's busiest airports are bad weather and overtaxed air traffic control equipment. Correct answer
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A is the correct answer since the choice provides alternative cause to the reason of the problem.
Since the solution is addressing to the probelem that is no loger there the plan is likely to fail.

A student just asked via message for more detail on the reasoning process for this question, and to help with the choice between answers A and C. I'll share my thought process:

We have a very big leap from the evidence to the conclusion. The evidence says that airport delays have increased by 25 percent. (Note to self: we have no idea - and definitely no evidence - on why these delays have increased.) The author somehow jumps to the conclusion that we need to allocate more of the takeoff and landing slots at the busiest airports to commercial airlines.

My reaction: ???? (scratching head) What???
Where is this conclusion even coming from?

What does the author assume is causing the delays??

He must think that the commercial airlines are causing the delays. Specifically, he must think that the problem is that the commercial airlines don't have enough takeoff and landing slots ... so if we can give them more slots (basically appointments on the calendar when they are allowed to take off and land) then this will alleviate the problem of delays. So he thinks.

What a dumb assumption. Sorry, author. There is NO evidence to back up this idea. If we can show that anything else (other than commercial airlines getting insufficient takeoff/landing slots) is the real cause of delays, we will prove what a dumb idea this is.

Answer choice A gives us some alternative causes of the delays. These causes have nothing to do with commercial airlines and their takeoff/landing slots. This is perfect - it proves how the author's idea would be pretty useless to combat the delays, since his idea doesn't address the real problems that are causing the delays.

Answer choice C gives us a fact about what percent of slots are currently assigned to commercial airlines. But we have no way to know if this is a sufficient percentage or an insufficient one. We have no other data (about how many slots the commercial airlines would actually need) to compare this to. So we can't use this to strengthen or weaken anything.

To generalize -> if the conclusion is based on an unproven assumption about the cause of some outcome, we can weaken the argument by finding any good alternative explanation to suggest that something else entirely is the real cause of the outcome.
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The stem provides some context and then a plan of action is recommended.
The plan of action is to allocate more of the takeoff and landing slots of the busiest airports to commercial airlines.
This is because the deregulation of airlines has increased the delays at the nation's busy airports by 25%.
The plan is based on the assumption that the cause of the delays is because commercial airlines don't have enough time slots i,e. that there is not other potential cause of the delays.

We are then asked to raise some doubt over the effectiveness of allocating more takeoff/landing slots to commercial airlines.

A is the answer as it highlights the assumption made. If an alternate cause of the delay exists, as is the case here, then allocating more commercial airlines to the slots mentioned won't do anything.
B is not conducive to the argument and in fact tries to trick the reader. 25% increase in airlines does not correlate with 25% increase in delays on average.
C provides a data point that we can't objectively assess. An 85% allocation may or may not improve the delay situation. If this statement said 100% then it would weaken the argument as the airlines would not be able to allocate anymore.
D provides a data point that doesn't really help our current situation as what worked for some may not work for others.
E is incorrect as it does not cast any doubt whatsoever over the plan. It merely expounds the severity of the situation by saying that not only have delays increased but they are also longer.
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We need to find a way in which even if more slots are given, the delays will not be resolved. This means that the cause of delays may have been something other
then the slots. Something which tells that the cause of delay is not slots but something else shall be our answer.

A: Yes. Looks like it. Contender
B: Opposite. Rejected
C: So what. Maybe 60 isn't enough. Rejected
D: So what. doesn't help our cause. Irrelevant. Rejected
E: So what. doesn't help our cause. Irrelevant. Rejected

IMO A

Wait, so B) tells us that the increase of number of airlines in operation could have been a cause of the increase in delays, no? I mean it wouldn't be the most logical explanation, but it could potentially weaken the argument, as it actually shows a correlation between the number of operating airlines and the delays. Hence, this weakens the argument: Even more operating airlines would increase delays even more.
Am i missing something?

Same here, i couldn't knock-out (B). Can someone help with B please.

Since the deregulation of airlines, delays at the nation's increasingly busy airports have increased by 25 percent. To combat this problem, more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines.

Which of the following, if true, casts the most doubt on the effectiveness of the solution proposed above?

Premise: Since the deregulation of airlines, delays at the nation's increasingly busy airports have increased by 25 percent.
Conclusion: more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines.

(A) The major causes of delays at the nation's busiest airports are bad weather and overtaxed air traffic control equipment. Correct. This brings in an alternate explanation to highlight another cause for increased delays. This weakens the argument.

(B) Since airline deregulation began, the number of airplanes in operation has increased by 25 percent. This strengthens the argument. It is in line with the stimulus.

(C) Over 60 percent of the takeoff and landing slots at the nation's busiest airports are reserved for commercial airlines. 60% does not tell us if it is a significant number or not. Eliminate.

(D) After a small mid western airport doubled its allocation of takeoff and landing slots, the number of delays that were reported decreased by 50 percent. Cannot compare a small airport with the nation's busiest airport.

(E) Since deregulation the average length of delay at the nation's busiest airports has doubled.This strengthens the argument.

Hi Experts,

Can anyone help me understand one thing here:

If the reason for air traffic is bad weather and old equipment, then what does it have to do with deregulation. Why is it mentioned "since deregulation"?

What I am trying to say is that, bad weather and bad equipment would be there before the deregulation as well as weather does not have control over anything.

I did not choose A because of the same reason. The reason being - it is specifically mentioned "since deregulation."

Please help.

HI moderators nightblade354, carouselambra

is this really an OG question?

Actually it says the answer is A. But Even before or after deregulation , the major causes of delays can not be changed.
How is it possible that delays now increased due to bad weather and overtaxed air traffic control equipment. It seems this bad weather and overtaxing started happening only after deregulation.


VeritasKarishma IanStewart : Please suggest your opinion. I am still scratching my head with optionC.

Since the deregulation, delays have increased by 25 percent. (We don't know what deregulation entails. We are not given what changed. We are also not given that deregulation is the reason for increase in delays. It has just been observed that since that time, delays have increased.)

To combat this problem, more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines.
Solution is that more slots should be given to commercial airlines.

What will weaken that this will fix the problem? If we get to know that the reason for delays is something else - say weather phenomena - then will giving more slots help? Probably no.
Only if the reason for increased delays is that the airlines have fewer slots than needed, then giving more slots will help.

(A) The major causes of delays at the nation's busiest airports are bad weather and overtaxed air traffic control equipment.

Correct. The reason for delays are different. More slots may not help. This weakens our conclusion.

(B) Since airline deregulation began, the number of airplanes in operation has increased by 25 percent.

If more planes are deployed now, more slots may actually help. Doesn't weaken our conclusion.

(C) Over 60 percent of the takeoff and landing slots at the nation's busiest airports are reserved for commercial airlines.

Irrelevant. Is 60% a high number or a low number, we don't know. If commercial airlines are responsible for 90% of the flights, then 60% seems low. If commercial airlines are responsible for 40% of the flights, then 60% seems high.

(D) After a small mid western airport doubled its allocation of takeoff and landing slots, the number of delays that were reported decreased by 50 percent.

What happened at a small airport is irrelevant. The nation's busiest airports are our concern.

(E) Since deregulation the average length of delay at the nation's busiest airports has doubled.

We already know the delays have increased. Doesn't weaken conclusion.

Answer (A)
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