GMAT Prep question

[kapilrs001]

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?

(A) The major causes of delays at the nation's busiest airports are bad weather and overtaxed air traffic control equipment.
(B) Since airline deregulation began, the number of airplanes in operation has increased by 25 percent.
(C) Over 60 percent of the takeoff and landing slots at the nation's busiest airports are reserved for commercial airlines.
(D) After a small midwestern airport doubled its allocation of takeoff and landing slots, the number of delays that were reported decreased by 50 percent.
(E) Since deregulation the average length of delay at the nation's busiest airports has doubled.

I did search for this question in the forum but I don't think this has been discussed
I picked B (OA is A). The reason I picked B is :-
This is the only solution that connects pre-derugalation time and present. A was a good contender but the problems of bad weather and overtaxed air traffic control equipment would have existed even before deregulation. Isn't it a coincidence that deregulation happened and these incidences became more common.
Please Ron kindly help me with this. Your explanations are awesome.
Big fan.

Kapil

[tim]

It looks to me like B would actually strengthen the argument - if the number of airplanes has increased (and particularly if that's the cause of the delays), then allocating additional slots to accommodate those additional airplanes would seem likely to alleviate the problem. On the other hand, if the bottlenecks are weather and air traffic control (as in A), allocating additional landing slots won't likely help the situation.

[RonPurewal]

the deregulation is actually irrelevant.
the author's point is that, if we give the commercial airlines additional runway spots, the delays will go away. so, you need evidence that additional runways will not make the delays go away.

if the problem is "there are too many planes", then the author's plan WILL help—regardless of why there are too many planes. (this is why choice (b) is not correct.)

we need to show that the problem is NOT "there are too many planes".

choice (a) is perfect: the delays are caused by factors that have nothing to do with "too many planes".
if choice (a) is true, then additional runway spots will do nothing to ameliorate the problem, since adding runway spots will neither change the weather nor relieve the burden on the air-traffic-control equipment.

[750plus]

What is the effect of choice C on the conclusion ? Please shed some light.

[RonPurewal]

What is the effect of choice C on the conclusion ? Please shed some light.

no effect at all, actually. there's no context that gives this 60 percent figure any meaning.

did you think otherwise?

[750plus]

What is the effect of choice C on the conclusion ? Please shed some light.

no effect at all, actually. there's no context that gives this 60 percent figure any meaning.

did you think otherwise?

I was thinking in this direction.

The argument stem says- ' To combat this problem, more of the takeoff and landing slots at the busiest airports must be allocated to commercial airlines. '

Now, C says 60% takeoff and landing slots are already reserved for commercial airlines, then why is there a need to add more space ! This in no way is going to help in resolving the problem.

[RonPurewal]

see, this is what i mean—you're just guessing that %60 is, in context, a 'big' number.
the problem is that you're guessing.

you would need the answer to something like 'Commercial airlines account for what percentage of all air traffic at this airport?'
if THAT number is more than sixty per cent, then, suddenly, %60 of runways seems like 'not enough'.

[750plus]

see, this is what i mean—you're just guessing that %60 is, in context, a 'big' number.
the problem is that you're guessing.

you would need the answer to something like 'Commercial airlines account for what percentage of all air traffic at this airport?'
if THAT number is more than sixty per cent, then, suddenly, %60 of runways seems like 'not enough'.

Yeah, makes sense. This is the mistake I did in this question.

I solved it in 1.40 minutes and somehow I was not able to see the effect of choice A. Consequently, I picked C.

I have added this in my error log and have taken 'a takeaway' for myself.

Thanks again.

[tim]

Glad to hear it. Let us know if you have any further questions on this one.

[RonPurewal]

I have added this in my error log and have taken 'a takeaway' for myself.

what is the takeaway?

it might be hard to explain, but give it a shot.

[750plus]

I have added this in my error log and have taken 'a takeaway' for myself.

what is the takeaway?

it might be hard to explain, but give it a shot.

Take away -

In the light of option C, do not take any number or percentage as a big or small number just by the fact that if it is more than 50 than that means a big percentage/number and vice versa.

If nothing is given about the number/percentage on the stem, evaluate it and take a decision.

Could I do some justice to what you asked.

Many thanks

Warm Regards

[RonPurewal]

yep, that's pretty much the point.

in fewer words:
the meaning of 'big percentage' and/or 'small percentage' depends entirely on context.

[RonPurewal]

also—
to cement these points in your mind, make up vivid, extreme, and/or dramatic examples.

e.g.,

I invented a drug that cures terminal cancer in 60 percent of all patients.
--> WHOA AMAZING DRUG. i will soon be the richest person in world history.

I invented a home security system that alerts the police to 60 percent of all break-ins.
--> WHOA TERRIBLE SYSTEM.

[750plus]

also—
to cement these points in your mind, make up vivid, extreme, and/or dramatic examples.

e.g.,

I invented a drug that cures terminal cancer in 60 percent of all patients.
--> WHOA AMAZING DRUG. i will soon be the richest person in world history.

I invented a home security system that alerts the police to 60 percent of all break-ins.
--> WHOA TERRIBLE SYSTEM.

yes, yes.

That makes it more clear )

Warm Regards
Rajat Gugnani

[tim]

Glad to hear it!