If the airspace around centrally located airports were restricted to

+1 C

There are tow types of private planes: those with radar and those without it.
Those with radar are allowed to fly in the restricted area.
Those without radar cannot fly in the restricted area, and they are a lot.

+1C
To be noted question is "Assumptions of the conclusion drawn in the first sentence"


(A)Outlying airfields would be as convenient as centrally located airports for most pilots of private planes. -- not concerned about airfields

(B)Most outlying airfields are not equipped to handle commercial-airline traffic. -- not concerned about airfields

(C)Most private planes that use centrally located airports are not equipped with radar. -- Correct --- There is a restriction for private planes without radar, coz of this most of planes are outside airport (means most of them are without radar)

(D)Commercial airlines are at greater risk of becoming involved in midair collisions than are private planes. -- We are concerned about private planes specifically not general commercial airlines

(E)A reduction in the risk of midair collision would eventually lead to increase in commercial airline traffic. -- This is assumption of final conclusion

Hi Himanshu,

Good question.

The question stem says that the conclusion in the first sentence. If we analyze the structure of the sentence, then we will see that the stimulus contains two opinions

i) most of the private-plane traffic would be forced to use outlying airfields.
ii) Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports.

The overall structure goes like this: First part of the fist sentence is the premise for i) and i) is used as a premise for the main conclusion ii).

i) is the intermediate conclusion, which the questions stem talks about.

We have to find an assumption that the author has to make to make his claim valid. Our assumption should validate that "most of the private-plane traffic would be forced to use outlying airfields"
First sentence says "only those private equipped with radar", so, the commercial planes not equipped with radar would not be able to use the airspace around the centrally located airport. Now, if most planes do not have a radar then they will be forced to use outlaying fields, reducing the overall traffic. Answer choice (C) does is very well, others could be true, but not necessarily validate the conclusion.

Hope that helps,

Vercules

Conclusion in first sentence- most of the private-plane traffic would be forced to use outlying airfields
Pre-thinking - Most of private planes that use centrally located airport are not equipped with radar .

Answer C

(A) Outlying airfields would be as convenient as centrally located airports for most pilots of private planes．
the convinience is not the central focus of the argument and thus is out of scope
(B) Most outlying airfields are not equipped to handle commercial-airline traffic．
the capacity of an airfield to handel the traffic is again out of scope of the argument.
(C) Most private planes that use centrally located airports are not equipped with radar．
Most apt answer choice since if you do negation test on this this will break the argument and there will be no need of using a seperate airfield
(D) Commercial airliners are at greater risk of becoming involved in midair collisions than are private planes．
protecting the commercial airliners is no tthe sole motive of the move to use the alternate airfiled all aircrafts are to be protected.
(E) A reduction in the risk of midair collision would eventually lead to increases in commercial airline traffic．
this is not the asumption this is a good conclusion but cannot be assumed from the given argument.

If the airspace around centrally located airports were restricted to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields.Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports

Since the objective is to reduce the traffic thereby reducing risk of midair collision at centrally located airports, retaining private places with radar to centrally located airports and shifting the rest of the private-plane traffic to outlying airfields would only result in reduced traffic at centrally located airports -> if the private planes with radar are much less than private planes without radar, which is what has to be the clear assumption of the one who is making this statement. Else there is no point in retaining the private planes with radar to centrally located airports if their quantity is not substantially less.
Therefore C is CORRECT

If the airspace around centrally located airports were restricted to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields.Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports

Conclusion: Reduction in mid air conclusion
Premise: Airspace = restricted = only comm/private planes with radars.
Private planes = Reduced = reduction in collision
Assumption: Private planes are without radars.

The conclusion drawn in the first sentence depends on which of the following assumptions?

(A) Outlying airfields would be as convenient as centrally located airports for most pilots of private planes．
They are changing the routes not because of convenience but because of safety ( Radar )

(B) Most outlying airfields are not equipped to handle commercial airline traffic．
Well we are talking about an assumption of collision of flights and not the handling.

(C) Most private planes that use centrally located airports are not equipped with radar．
My background information

(D) Commercial airliners are at greater risk of becoming involved in midair collisions than are private planes．
Who is at a greater risk is not ou concern. Why the reduction happened is our concern.

(E) A reduction in the risk of midair collision would eventually lead to increases in commercial airline traffic．
Out of scope.

If the airspace around centrally located airports were restricted to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields. Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports

The conclusion drawn in the first sentence depends on which of the following assumptions?

conclusion drawn in the first sentence - most of the private-plane traffic would be forced to use outlying airfields

(A) Outlying airfields would be as convenient as centrally located airports for most pilots of private planes．
As per the above argument, most of the private-plane traffic would be forced (they have no choice or any other possible option) to use outlying airfields due to the restriction of the airspace around centrally located airports to only those private planes, which are equipped with radar. It does not talk about whether the outlying airfield would be as convenient as centrally located airports or not. Thus, this option is incorrect.
Convenience related to airfield usage is not talked about in the argument, so is irrelevant as we cannot comment on that.
The conclusion need not assume that outlying airfields are convenient for private planes, since the restrictions would give planes (that are not radar equipped) any/no choice.


(B) Most outlying airfields are not equipped to handle commercial-airline traffic．
Negate - Most outlying airfields are equipped to handle commercial-airline traffic．
As per the premise, the centrally located airports should be restricted to commercial airliners and private planes equipped with radar.
So, it does not matter even if the outlying airfields are equipped to handle commercial-airliners because commercial airliners will still be using the centrally located airports. The negation does not break the argument and the argument stands as it is. Therefore, this option statement is not an assumption.

(C) Most private planes that use centrally located airports are not equipped with radar．
Negate - Most private planes that use centrally located airports are equipped with radar．
This negation will break the conclusion of the first statement, if most of the private planes are equipped with radar, then most of them will be using the central located airport and not the outlying airfields. (most of the private-plane traffic would be forced to use outlying airfields).
Therefore, this is the assumption.

(D) Commercial airliners are at greater risk of becoming involved in midair collisions than are private planes．
This cannot be the assumption for the first statement. Also, this option statement goes against the main conclusion of this argument.

(E) A reduction in the risk of midair collision would eventually lead to increases in commercial airline traffic
Firstly, this is talking about the future, which may or may not be true to happen.
Secondly, this option statement does not provide a missing gap between the premise and the conclusion in the first statement.


Also, options B, D and E, which deal with commercial planes and with risk of midair collision, need not be assumed. As the conclusion of the first statement deals with the volume of the private-planes traffic and not with the mid air collision or the commercial planes.

Assumption

My Notes:
To find the assumption (unstated premise/evidence) of this type of question:
1.Identify question type 2.find conclusion 3.find evidence (premise) 4.find assumption (gap) 5. Denial/ Fact/ Negation Test (Pls use logical opposite) - The Correct Ac will "break" the author's arguement

Logical Opposite: All 100% Vs NotAll 0~99% , Some 1~100% Vs None 0%
Space: Everywhere, Noteverywhere, Somewhere, Nowhere
Frequency: Always, Not always, sometimes, never
Most = majority 51%-100%
several/ few = 3% - 100%
Polar Opposite: All Vs None

--------------------------------------------------------------------------------
My analysis:
Question Que: "which of following plans, ...best pospect..."
Question Type: Assumptiom

Conclusion:*first sentence
if airspace usage restricted to ONLY commercial airlines and ONLY Private with radar, then will reduce collision

Evidence:
(51%-100) Most private plane will be force to use outlying field

Assumption (pre-thinking that closes the gap):
(51%-100) Most private plane "WITHOUT RADAR" will be force to use outlying field

Denial/Fact test:
(0%) None private plane "WITHOUT RADAR" will be force to use outlying field
(personalize: If (100%)ALL are equipped with radar, then move what???)

Answer Choice B:
(C) Most private planes that use centrally located airports are not equipped with radar.

See the highlighted/underlined part
"....to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields. Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision ..."

Mostly private planes are without radar and operate around the centrally located airports and this is what option C tells us about.

Answer C.

If the airspace around centrally located airports were restricted to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields. Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports

The conclusion drawn in the first sentence depends on which of the following assumptions?


(A) Outlying airfields would be as convenient as centrally located airports for most pilots of private planes.

CONVENIENCE is not something that we care about for making this argument work. The conclusion here is that a reduction in the amount of private-plane traffic would reduce the risk of midair collision around centrally located airports.

(B) Most outlying airfields are not equipped to handle commercial-airline traffic.

Again, not essential. We don’t need to assume that outlying airfields are not equipped for commercial planes to think that private planes can be sent out there.

(C) Most private planes that use centrally located airports are not equipped with radar.

Correct. The entire argument is predicated on this idea that private planes can be sent outwards and that would in turn, reduce the traffic. But, suppose most planes were in fact equipped with radar – the argument folds – traffic and midair collisions would not necessarily decrease.

(D) Commercial airliners are at greater risk of becoming involved in midair collisions than are private planes.

Counter-intuitive and does not go in the direction we want.

(E) A reduction in the risk of midair collision would eventually lead to increases in commercial airline traffic.

Again, not the direction we want.

VeritasKarishma:

Am I correct when I say that this question has two conclusion statements - 1st and 2nd sentence. However, 2nd sentence is the conclusion of the argument and 1st sentence acts as a premise for the conclusion of the argument (i.e. 2nd conclusion statement)?

Thanks,

The structure of the argument is:

If A happens, B will happen.
Conclusion of the argument: B will reduce the risk of C.

The conclusion drawn in the first sentence is "B will happen." Based on this (often called the intermediate conclusion), the conclusion of the argument is drawn in the second sentence.

KarishmaB Ma'am,

Is my negation for answer choice C correct?

This is the correct answer choice because if most private airplanes are not equipped to use radar, they would automatically be diverted to the outlying air fields. This strengthens our conclusion.
When we negate this option statement we get "Less than or upto 50% of the private planes are not equipped with radar". So if this is the case then there are fewer planes that don't use radar. Hence, fewer would be forced to use outlying air fields. This weakens the conclusion. Hence, this is the correct answer choice.

Yes, this is correct.

Posted from my mobile device

Hi, the 1st statement in the question says that if the airspace around centrally located airports is ''restricted" to commercial flights and private planes only with radar, most of the private plane traffic would be forced to use outlying airfields. Now, isn't this a fact?

If we take this as a fact, we KNOW for sure that most of the private planes will not use the airspace around centrally located airports.

Now, the 2nd statement says - ''such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports''. So, given the fact in the 1st statement, the reduction of private planes in the airspace around the centrally located airports is bound to happen and that will reduce "risk of midair collision". Therefore, that reduction will reduce risk of midair collision is our main conclusion.

Then, how can option C be the right choice - Most private planes that use centrally located airports are not equipped with radar?
We already know, for a fact, that since the private plane reduction in the airspace around the centrally located airports is bound to happen (as mentioned in the 1st statement), they must not be equipped with radar (inferring from the fact).

Please help. GMATNinja KarishmaB egmat

Focus on the question stem:
The conclusion drawn in the first sentence depends on which of the following assumptions?

It is talking about the CONCLUSION drawn in the first sentence.

First sentence:
If the airspace around centrally located airports were restricted to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields.

Highlighted is the conclusion.

If A happens, B will happen.
Conclusion is that B will happen.

How can we say that most private places would be forced to use outlying airfields? Because they must not have radar.

Answer (C)

The second sentence of the argument is useless information because the question stem has only focused on the first sentence.