City X's goal is "to reduce traffic congestion."

To achieve this goal, the city came up with an ingenious plan:

• It would "encourage people who work downtown to sign a form pledging to carpool or use public transportation for the next year." If downtown workers who currently drive alone switch to carpooling or using public transportation, fewer cars would be on the road and thus traffic congestion would be limited.
• To incentivize signing the pledge, they would offer a coupon for a free meal at any downtown restaurant. Everyone who signs the pledge will receive this coupon.

From the answer choices, what MUST be true in order for the plan to succeed in reducing traffic congestion?


(A) contains a few strong modifiers. For the plan to succeed, does EVERYONE who signs the pledge need to FULLY abide by it for the next year?

Not necessarily. Even if just SOME of the pledge-signers carpool or use public transportation, traffic will be reduced. Similarly, if people just PARTIALLY abide by the pledge (e.g., they take the bus once a week and drive on other days), then traffic will be reduced.

Because the plan can succeed even if not everyone who signs fully abides by the pledge, (A) is not the correct answer.


Does (B) have to be true in order for the plan to succeed? Nope. Maybe everyone agrees that the downtown restaurants are worse than restaurants elsewhere. Still, if you offer them a coupon for a free meal, perhaps they will sign the pledge and go to a restaurant that they don't really like that much (I mean... free food, come on!).

And really, the plan doesn't DEPEND on people actually using the coupons -- it depends on people carpooling or using public transportation. Maybe some downtown workers will sign the pledge because they think it's a good idea, regardless of how likely they are to actually use the coupon.

(B) is out, because the plan can still succeed even if the downtown restaurants suck.


Again, modifiers play a key role here. For the plan to succeed, does MOST downtown traffic congestion need to result from people who work downtown?

Nope. Notice that the passage doesn't specify how much the plan will reduce traffic -- even a very small reduction in traffic would be a success. So, even if just SOME of the traffic results from downtown office workers, the plan could reduce traffic congestion a bit.

Because the plan doesn't require MOST downtown traffic to result from downtown workers, (C) is out.


Modifiers strike yet again! For the plan to succeed, does it need to be the "MOST EFFECTIVE" way to reduce traffic?

Not at all. There could be other, more effective ways to reduce traffic congestion -- banning cars, for instance, would really cut down on traffic. But the solution outlined in the passage can still succeed in reducing traffic, even if more effective solutions exist.

Eliminate (D).


Here we go. According to the passage, everyone who signs the pledge will receive a coupon. So, in mentioning "people who receive the coupon for a free meal," (E) is really discussing people who sign the pledge.

City X's plan will only be successful if people who sign the pledge actually carpool or use public transportation. If they just sign the form to get the coupon (again, free food!) and don't actually change their commuting habits, then the plan will not reduce traffic congestion at all.

(E) must be true for the plan to reduce traffic, so (E) is the correct answer.

I hope that helps!
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This question is not ambiguous for sure.

In must be true Question, we need the argument to hold true in all case.

Here the goal is to reduce traffic.(keep in mind even if it is reduced by 1% or 100%, the plan will succeed)

A -Everyone who signs the pledge form will fully abide by the pledge for the next year -- consider 100 people signed the petition, A says if all 100 people abide the pledge, then we can reduce the traffic but this is not logical. even if 50 people abide the pledge, traffic will be significantly reduced. so, this is not true all the time. Eliminate

C- Most downtown traffic congestion in City X results from people who work downtown. C says more than 50% of the traffic is caused by people who work in downtown. But this need not to be true all the time. consider 40% percent of the traffic is caused by people who work in downtown and they signed and abide the pledge. This will still result in reduction of traffic. Eliminate


E At least some people who receive the coupon for a free meal will sometimes carpool or use public transportation during the next year.

Just negate E- No people who receive the coupon for a free meal will sometimes carpool or use public transportation during the next year. If no one is using the carpool or public transportation then the traffic will be same and the plan will fail. So, E needs to be true.

I consider this one a bit tough because there is an "obvious" correct choice with A. If you are Tigger happy you might jump for it! Nevertheless, always be skeptic of options with "hard" language.

In CR i like to 1. Read the questions objective and 2. understand the key players, 3. Read carefully and synthesisze. 4, Read answer carefully

1. Objective: Assumption , plan will succeed... Plan = Less Congestion -> Sign Pledge if yes, Cupon R (incentive )
2. Player: Transportation Bureau ( I just type TB to save time).

A. Looks nice . Will keep it in the back pocket. Suspicious because of "hard" word 'everyone'
B. Irrelevant to the plan success
C. Also tricky. Because, its easy to think that "are the people downtown causing the traffic? maybe others who won't get a cuppon. Keep in back pocket.
D. Train wreck of an answers. Eliminate.
E. Looks nice! Now time to triage.

A. Hard language choices tend to be wrong. Let's follow our habits and eliminate.
C. Does not mention the plan. So the question can be out of focus. Maybe a lazy test writer. Eliminate.
E. Soft language, mentions plans , and effect. Choose it. Move on with your life. Answer the question in less than 2 min do something else.

The question is ambiguous, so don't be too hard on yourself. Use it as a practice to eliminate wrong answers. And then carefully triage what is left. Don't stay too long on this question! It's not wroth it. You want to get through all 36 questions!

Hey, could help with why C is incorrect?
E seems too soft as per me vs C
C strikes the heart of the question. If the traffic isn't caused mostly by the downtown office goers then how can this plan work since the TA of the plan is them.

Ok I'm back.

TARGET: Find an option that must be true for plan to succeed.
Pre-think: For the plan to succeed everything should happen as thought by the bureau.

ERRORS:marked red in question . This question is a good example for extreme option elimination.


A) Everyone need not do that: at least some >>> traffic declines. EXTREME option

B) Ok so what preference of restaurant ? May be people prefer these restaurants and collect coupons and then violate the pledge.

C)It need not be most. Even little reduction is also OK. EXTREME

D)It need not be most effective but still effective enough . EXTREME

E)PERFECT: Atleast some people does as expected>>>> plan succeed.i.e, at least some traffic reduction is inevitable.
In extreme options search for Soft tone choice that fits our requirement


HOPE THIS HELPS

THANKS.
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Initially I chose A, but after solving similar questions, I am leaning towards E. Here are my thoughts:

Plan: To reduce traffic congestion, Bureau is considering plans to encourage people to pledge. How? The pledged people will get meal coupons.
So, the hidden linkage is, provide meal coupons -> reduce the traffic.

Now the question part: Question stem asks if the plan is to succeed, which of the following must be true?.

A : Here is where I faltered. I have considered only the pledge not the meal coupons. I am not skeptical of strong language, but this does not affect the linkage between meal coupons and reducing traffic. If only pledging is required to reduce the traffic, then there is no need for meal coupons. If you want to be conservative, keep A.

B. People preferring restaurants is not our concern Eliminate B.

C. Most traffic congestion is caused by people from downtown. Okay. But does the plan is to reduce the traffic only from people from downtown? NO, the plan is reduce the the overall traffic congestion. More subtly, this does not address the plan of giving coupons-> reduce congestion

D. Again, this does not address the plan of Bureau

E. Okay, the contender for A. At least some people who receive coupons, will stick to the pledge. Keep E.

Between A and E, which of the options are need for the plan to succeed?

Negate A (certainly this is not assumption question, but let's try out!)

No-one who signs the pledge form will fully abide by the pledge for the next year. Cool! but wait.. there is another version

Everyone who signs the pledge form will not fully abide by the pledge for the next year. Will this plan work by then? Certainly! Even if they use other means of transport, or simply carpool on different days, then the traffic congestion is reduced.

Now get back to E.

No one who receives the coupon for a free meal will sometimes carpool or use public transportation during the next year. Since No one is used, sometimes is meaningless here. Okay this does not hold out. Let's try another variation

At least some people who receive the coupon for a free meal will never carpool or use public transportation during the next year. -Even this second negation, will result in the failure of the plan.

So, E is absolutely required for the plan to succeed, but A is not necessarily always required for the plan to succeed.

Let me know whether the explanation helps, and any corrections are always appreciated!

why not A when the question asks says "must be true?"
A gives me clear answer that it will definitely reduce the traffic congestion

in E, what if some people ( say 365 people), follow traffic on each day one by day - this could reduce traffic very negligibly
Secondly , what if 365 follow on the same day, then what about other 364 days? traffic is not reduced in 364 days, so weaken the conclusion.

This question has too many open ends.

Not clear on how to eliminate A? Both A and E solve will reduce traffic. Some clarity on this will really help.

Thanks

It's not too ambiguous tbh. Let me break it down for you.

It's about traffic, not downtown traffic. that eliminates some options. Also, it's not very extreme so it's a good option.

Hello, everyone. I see a lot of confusion above in the responses, particularly about answer choice (A), so I thought I would provide a full analysis to hopefully clarify a few points. How about we start with the question?


Notice that the frame of this question adopts the phrase must be true. You could think of this as a necessary assumption in a different question with that keyword (assumption) instead. Be careful in these questions not to justify a could-be-true answer. Many people overlook the obvious because they think there has to be some deeper purpose or meaning, but that is not the way standardized tests operate in general, least of all on this type of question.

The passage is easy enough to digest.

Sentence 1 lays out the plan. The transportation bureau wants people who work downtown to sign a form, one that says they will carpool or use public transportation for the next year. The why is spelled out for us in the first few words: to reduce traffic congestion.

Sentence 2 does not offer any commentary, merely informing us that everyone who signs the form will get a coupon, one that entitles the bearer to a free meal at any restaurant in the downtown area.

The linear relationship is as follows—plan: (sign a form = coupon) → reduced traffic congestion. Our answer must tie into this relationship. (An alternative explanation will not do here.)


The only information the passage provides about everyone is that each person who signs the pledge will receive a coupon. Not to be overlooked is the equally absolute will fully abide by the pledge. What would it mean to partially abide by the pledge? Would workers who opted to get their legs moving on Bike to Work Day fall into this undesirable category? Would that situation not also potentially reduce traffic congestion? We are looking for a must-be-true answer, and if, in a pretty unrealistic, happy-go-lucky scenario, 99 percent of all pledges followed through but 1 percent did not (the ones who might have just wanted a free lunch), and traffic congestion were subsequently reduced, would that not also make the plan a success? We should be able to appreciate that these extreme conditions do not have to hold for the plan to achieve its aim, so we need to keep looking for our answer.


This is the right group of people, the target group of the plan, but restaurant preferences have nothing to do with its success. If I worked in the city and packed my lunch everyday to save money, or perhaps because I felt that a homemade meal was more wholesome and healthful than the fare offered at restaurants in general, but I then got a coupon for a free meal at any downtown restaurant, I might decide to treat myself one day to the free meal or take a friend out. The point is, I could take the coupon regardless of my restaurant preferences, and so might anyone else. As long as pledges stuck to what they pledged to do, the plan could be a success. The coupon is just icing on the cake.


Make every word count, or else you should be skeptical of the answer. We can only speculate whether most traffic congestion is caused by downtown workers or by journey-workers passing through the city each day to reach their eventual destinations. The goal of the plan is to reduce traffic congestion, plain and simple. Perhaps there are just more buses and other forms of public transit into the downtown area than there are to other surrounding areas, so the transportation bureau decided to provide an incentive for a proportion of commuters, some proportion, the one that consists of people who work downtown, to use public transportation or carpool. We have no numbers in hand to qualify most. Maybe a 30 percent reduction in traffic congestion would be considered a success, and perhaps that very sliver of congestion is currently caused by people who work downtown. It is an extreme case, but a must-be-true question forces us to confront such possibilities, and we have found a loophole.


Another superlative in most, and another answer that is easy to see off for overstepping its bounds. We are not privy to the information behind the decision by the transportation bureau to offer people who work downtown a meal voucher to sign the pledge. It could have been some last-ditch effort to reduce traffic congestion after other potentially better ideas had already failed. We will never know, nor should we be concerned with what could be the most effective way to address the problem. The bureau proposed a plan. Does that make it the best possible plan by default? I wish such issues could be resolved so simply in real life.


What do you know? The plan that hinges upon people pledging to do something in exchange for a coupon actually requires some of these people to follow through sometimes for the plan to succeed. Who would have guessed? Note that we are not trying to find an answer to justify whether the plan will be successful, only what it would take for this particular plan, by its very design, to be successful. This is a must-be-true condition, and with the other answers safely out of the way, there is no room for doubt anyway. Choice (E) is our answer.

I hope that helps. If anyone has further questions, I would be happy to offer my thoughts. As always, good luck with your studies.

- Andrew

Hey Andrew,

Very nicely explained.

I have some doubts in option B.



Thinking this, I thought B is better than E. I get why E is correct but the point is that I am not able to eliminate B.

Please help.
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Hello, warrior1991. I understand how you could follow such a train of thought. On the other hand, whether people prefer downtown restaurants to others is beside the point. If you worked downtown and took your lunch breaks there simply for convenience, then you might understandably be interested in a coupon for a free meal, regardless of whether you would rather be eating somewhere else.

For the record, I think the plan sounds terrible. I cannot imagine anyone taking such a pledge seriously—sacrifice a year of convenience in driving yourself to work (alone) for one free meal?—but at the same time, the plan hinges upon people following through on their commitment, and the incentive behind that commitment is an irrelevant concern. A restaurant coupon could just as easily be swapped out for a trip to the circus. As long as people do what they say they will do upon signing the form, the plan could succeed.

If you prefer the negation technique, you can also check (B) and (E) that way:

(B) At least some No people who work downtown prefer the restaurants downtown to those elsewhere.
(E) At least some No people who receive the coupon for a free meal will sometimes carpool or use public transportation during the next year.

If (B) is true, the plan could still succeed, even if its likelihood of success is diminished. But if (E) is true, and the people who signed the form never carpooled or used public transportation in the next year, then there is no chance for the plan outlined in the passage to get off the ground. It would take some alternative plan or factor to address the problem of reducing traffic congestion.

- Andrew

With Must be true questions, a simple trick to find wrong answers is to come up with scenarios where it musn't be true. Similar to the quant section..

a) Do we need 100% participation for it to work. If 20% of people carpool, then traffic was reduced, this 100% participation ain't necessary

c) Let's say people working downtown don't represent most of the traffic downtown. That can be anywhere from 0% to 49%. IF we reduce the traffic in 49% of drivers, we have reduced traffic. So this isn't a necessary condition.

Also, good to visualize, if 49% of traffic is from people working downtown, they can still be the largest group among all other groups that comprise downtown traffic

e) yes! if not even 1 person participates, then there is no way this plan is going to work

For its worth, the most important thing to remember is 'MUST BE TRUE'

GMATNinja please help with this one!

Hey folks!

This question is very interesting - it tests us on our application of the Must Be True (MBT) characteristic of an assumption.

Here is a video solution we made for this question.





We hope you enjoy solving this question as much as we did .


Regards
Harsha
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GMATNinja In eliminating option C, my reasoning is that even if Most downtown traffic congestion in City X results from people who work downtown, it doesn't mean that they will carpool or use bus given the incentive as per the plan. Is this reasoning not correct?

It seems like you may be getting mixed up between what must be true in order for the conclusion to be properly drawn (a necessary assumption) and what would, if true, ensure that the conclusion would logically follow (a sufficient assumption).

This question asks that we find an answer choice that must be true (a necessary assumption). This means that the answer choice does not, by itself, have to ensure the transportation bureau’s plan will succeed.

Instead, as we said in the post you quoted, we ask ourselves whether it must be true that most downtown traffic congestion results from downtown workers in order for the bureau’s plan to successfully reduce traffic congestion. Because the bureau is merely aiming to reduce (and not eradicate or eliminate the majority of) traffic congestion, it does not have to be true that MOST of the downtown traffic results from downtown workers. As long as some of the traffic results from people who work downtown, it’s still possible for the plan to reduce traffic congestion because even one fewer car on the road would be a reduction in traffic congestion.

For that reason, (C) does not have to be true, and we can eliminate it.

I hope that helps!
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