If a person chooses to walk rather than drive, there is one less vehic

E is a classic shell game.

If people could walk whenever it is feasible, then pollution is greatly reduced.
walking alone reduces pollution? consider biking as well!!!!

So C is the answer, author is assuming that walking in the only way to reduce pollution. He is totally ill-concerned of other alternatives.

Negation for sometimes is never
People never drive when it is feasible to walk instead. Thus they already try to walk when they can but the polution has not decrease-> against the conclusion. Thus it is E

Ans Exp

Here the conclusion:- then pollution will be greatly reduced so in an assumption question we should always support the conclusion so we should prove that the pollution would be decreases if which of the following is done here i use Negation technique for each option

a. Cutting down on pollution can not be achieved in a variety of ways. so this statement is showing that pollution cannot be reduced which is quite opposite to the conclusion so eliminate it
b.Taking public transportation rather than driving is always feasible.i negated this choice by eliminating not so by negating this option states that taking public transportation system rather than driving is feasible so if people follow this then pollution get reduced but we don't know that people are following this so we cannot conclude that pollution reduces so eliminate this option.
c. Walking is the not only feasible alternative to driving that results in a reduction in pollution. so this statement after negation states that there are another methods to reduce pollution so by this we cannot definitely say that pollution can be reduced as we don't know that other ways are most effective ways to reduce pollution that walking so eliminate this.
d.There are people who never drive but who often don't walk so by negating this option says that some people will never drive and never walk so the pollution from such people will neither increase or decrease, so eliminate this option.
e.People sometimes don't drive when it is feasible to walk instead, so by negation this option states that when people have chance of walking they walk they use vehicle only when walking is not feasible so by such people the pollution can be reduced to some extent so which supports the conclusion so the Answer option is e.

Hope it's clear.

Wow..lot of mixed opinions on this one.

Everyone seems to agree that it cannot be A,B or D.

So, here are my 2 cents on C and E.

IMO it should be E since argument states:
1. Cars emit pollution
2. People drive cars.
2. People walk, pollution low.
3. If feasible for people to walk, pollution low.

So, the (1st) assumption that jumps out to me is: people don't always walk. So, E comes closest.

Now, why not C, the argument never ONCE stated that walking is the only solution, it just said pollution will be greatly reduced...NOT most reduced.


Always make a habit to avoid extreme cases such as this one in assumption choices.(Or atleast keep them in the back of your head).

Hope I helped.

A) Cutting down on pollution can be achieved in a variety of ways. - Too generalised statement to be an assumption - Incorrect
B) Taking public transportation rather than driving is not always feasible. - No mention of public transportation in the premise - Incorrect
C) Walking is the only feasible alternative to driving that results in a reduction in pollution. - Usage of word "only" is too strong in the present context. Cannot qualify to be an assumption - Incorrect
D) There are people who never drive but who often walk. - Passage is talking about the people who drive but not who does not - Incorrect
E) People sometimes drive when it is feasible to walk instead. - Author concludes that if people walk when it is feasible for them to do so, the pollution will be reduced substancially. To state this, it can be assumed that though people can walk small distances, they still tend to drive which contributes to the pollution. - Correct

Hope the explanation helps.

If i negate E, people never drive when it is feasible to walk. How will this destroy the argument?

Also confused between E and C.

If a person chooses to walk rather than drive, there is one less vehicle emitting pollution into the air than there would be otherwise. Therefore if people would walk whenever it is feasible for them to do so, then pollution will be greatly reduced.

Argument : 1 less person to drive= 1 more person to walk .. if this happens there will be one less vehicle emitting pollution.
Conclusion : If above is true… POLLUTION will GREATLY REDUCE.

Note : “IF” we are already considering a condition. SO if there is an answer that says people don’t walk then that answer is useless as we are already are considering a “if” condition.
“GREATLY REDUCE” : Just reduce is fine…but “greaty reduce” is a large proportion …this is a major hint.
ASSUMPTIONS: The author may be basing his conclusion on various assumptions. LETS dig them one by one.

Think : what if even if people walk , the pollution will not GREATLY reduce : this will happen if the pollutiotn creaed by the vehicles is almost negligible (please do not assume that vehicles ceate a lot of pollution IN CR do not use extra brains). So if the pollution is negligible, then poluution willreduce but not GREATLY.
Assumprion 1 : There is a considerable amount of pollution emitted by vehicles

What if the condition “if people walk when feasible” already exists?? But still the pollution is there…so even of we consider the condition there may not be any change !!
Assumption 2: There are people who drive even when its feasible to walk.

Which one of the following is an assumption on which the argument depends?

A) Cutting down on pollution can be achieved in a variety of ways.
GREAT ..so what??? Will walking do any good?? No answer !!

B) Taking public transportation rather than driving is not always feasible.
PUBLIC TRANSPORT – out of scope

C) Walking is the only feasible alternative to driving that results in a reduction in pollution.
“only” author never says that walking is “only” alternative. He just says that walking will reduce .

D) There are people who never drive but who often walk.
-OUT of scope. We want to talk about people who drive and would walk.. but this options talks about people who never drive

E) People sometimes drive when it is feasible to walk instead.
-CORRECT

VeritasPrepBrian I agree with your statement about E. However, if we negate C and say "Walking is NOT the only feasible alternative to driving that results in a reduction in pollution" we hurt the conclusion of the argument, don't we? Negated option C means that there are some other ways to reduce pollution, so walking would not necessarily greatly reduce the pollution.

So, both C and E, if negated, seem to hurt the conclusion of the argument. How do you choose the better option?

Really good question, and the mistake you're making with your analysis of C is a really common one. Note that the conclusion says:

Therefore if people would walk whenever it is feasible for them to do so, then pollution will be greatly reduced.

Here's what's critical: the goal here (or result, I guess) is to reduce pollution. And we know that walking instead of driving reduces the pollution that would have been released by driving. So the plan - I'll walk instead of driving - accomplishes the goal. And that's regardless of whether there might be a second plan that would ALSO accomplish the same goal. What we're tasked with here is really determining "will walking instead of driving reduce pollution?" - what you're doing with (C) is answering a tangential question, which is more like "is walking instead of driving the best solution to reducing pollution?" or "is walking instead of driving the only possible solution to reducing pollution?" But that's not what's being asked.

Whether someone could skateboard, rollerblade, bike, or kayak instead of driving and similarly reduce pollution doesn't change the fact that walking reduces pollution. So those other transportation suggestions don't weaken the conclusion.

Note: you see this a ton whenever a CR prompt talks about a plan or strategy to accomplish a goal. One huge them is that "the existence of a better plan doesn't weaken this plan." The better or alternate plan is a classic trap answer, but if the conclusion is "this plan will achieve this objective" then other plans don't matter - the task at hand is determining whether this plan will really accomplish that objective.

VeritasPrepBrian I understand your reasoning, thank you. However, here is why I am still in doubt about C.

The author strongly believes that walking is the way to reduce pollution, because he uses the word "greatly". Alright. To support his reasoning, we should eliminate the possibility that there is any alternative way to reduce pollution (or in the words of PowerScore CR Bible - "eliminate an alternate cause for the stated effect"). And answer choice C does exactly that - it says that "walking is the only way to reduce pollution"; this statement strengthens the argument that the author makes.

If the conclusion did not contain the word "greatly", I would definitely eliminate answer C. What is your thought?

This is good - thanks for keeping the discussion going. The problem with your logic on (C) - "greatly" doesn't compare walking to any other solution. It just says that if people walk instead of driving, that will reduce pollution by a lot.

And even if there are a thousand other modes of transportation that could reduce pollution, the existence of those doesn't change the fact that walking could still reduce it "greatly" or by a lot. The conclusion doesn't say that walking is the *best* (or greatest) way of reducing pollution...it just says that it can have a great impact. The existence of other methods of reaching a similar goal doesn't mean that this one can't have a great impact.

An analogous situation, if your goal is to greatly increase your salary, and your plan is to get an MBA, my saying "you know learning Python or Javascript can also increase your salary by a lot" doesn't mean that your MBA plan is a bad one. There are alternatives, sure, but those alternative routes don't mean that your plan is a bad one (otherwise then if you play the logic out, pretty much every plan is a bad one because in very few cases is exactly one plan the *only* way to get to a goal). If I wanted to weaken your MBA plan - which I do not! - I'd have to show evidence that your salary won't necessarily increase (e.g. "economists are predicting a recession that will freeze hiring, so those exiting college and graduate programs over the next 2-4 years will likely be unable to find jobs that even replace their current incomes" or something).

And a note on that quote from PowerScore - I'd be really surprised if that was in a chapter related to Assumption questions like this one. You don't need too much tweaking to the conclusion here to make (C) a good Strengthen answer (if it's "if people want to reduce pollution, they should walk whenever it's feasible to do so" then (C) is perfect as a Strengthen answer by eliminating other alternatives to walking). But Assumptions are necessary premises that have to be true in order for the argument to hold. And ruling out an alternative option or several is rarely NECESSARY unless the conclusion is specific about exclusivity (that this is the best or only way for something to happen, and not just "a way to achieve the desired effect").

Mykrasovski,

I agree with Brian’s analysis, but let me add further explanation here.

You said that negating C would also hurt the conclusion.

1. I doubt that negating C actually harms the conclusion. If there are other things that would also reduce pollution, that means they’re not being done, right? So doesn’t walking still help, *relative to the present status quo*? And even if the other helpful things were being done, wouldn’t also walking reduce pollution even more?

(Here I am reminded of an old LSAT question that basically says, “A company can improve its situation in only two ways, A or B. B is better than A, so when company chooses to do B, it is doing as much as possible to improve its situation.” What’s the flaw? The answer is, “The argument fails to consider that the company might improve its situation even more by doing BOTH A and B.”)

2. Your concern would be much better-founded if the conclusion was that walking was the ONLY way to greatly reduce pollution. In that case, ruling out alternative possibilities would become quite relevant. That may be the context of the PowerScore quote, if I had to speculate.

3. There’s still another issue at play here. Let’s imagine just for the sake of argument that negating C would, as you said, “hurt the conclusion.” Right answer, then? Still no. Assumptions are things that are not merely useful but in fact *necessary* to the conclusion. Living without a necessary condition isn’t just inconvenient or hard or painful. It’s impossible. Negating the right answer shouldn’t “hurt” the conclusion — it should *murder* the conclusion. AT A MINIMUM we should be able to say “well, now there’s NO basis or support whatsoever for believing the conclusion.” If you hold C to that more accurate standard, I hope it’s easier to see how far it falls short.

Does any of that help?

VeritasPrepBrian GMATNinja

Just wondering -- can (E) be an inference as well ?

Really good question! And yes...that's one thing that tends to be a big difference between Assumption questions and Strengthen questions, that in Assumption questions the correct answer is necessary in order for the rest of the argument to hold. So often/usually (I'll stop just short of saying "always" since that's so hard to prove, but man I'm having a hard time thinking of when it wouldn't be...), the right Assumption answer must be true in order for the rest of the stimulus to also hold true. And that means that you could view the correct Assumption answer also as a valid Inference because it meets that same Must Be True standard that Inferences need to.

Here, if we were to take "if a person chooses to walk rather than drive, there is one less vehicle emitting pollution into the air than there would be otherwise" and "if people would walk whenever it is feasible for them to do so, then pollution will be greatly reduced" as facts, then the fact that pollution would be greatly reduced (compared to now) means that currently not everyone who could walk rather than drive is walking, so that would mean that (E) has to be true.

And I think a big takeaway for future questions - correct Assumption answers are necessary premises in order for the argument to hold, so they "must be true" for the argument to work. So "must be true" is a great standard to hold these answers up to.

That's also why the Assumption Negation Technique works so well particularly when the answer isn't readily obvious - it forces you to consider what would happen to the argument if the correct answer were not true (if it failed the "must be true" standard). Correct Assumption answers are critical to the validity of the argument.

(A) Cutting down on pollution can be achieved in a variety of ways.
>try negating the above, “Cutting down pollution can be achieved in 1 way” this neither strengthen nor weaken the argument, so eliminate

(B) Taking public transportation rather than driving is not always feasible.
>Irrelevant

(C) Walking is the only feasible alternative to driving that results in a reduction in pollution.
>try negating the above, “Walking is not the only feasible alternative…….” this neither strengthen nor weaken the argument, so eliminate

(D) There are people who never drive but who often walk.
>try negating the above, “There are people who drive and often walks”, the negated statement dosent destroy the argument, so eliminate

(E) People sometimes drive when it is feasible to walk instead.
>try negating the above, “People don’t drive when it is feasible to walk”
the negated statement implies that there would no pollution created in the first place, if people walk. So this dosent bring down the current existing pollution,

Conclusion:
Pollution will be greatly reduced.

Apply the NEGATION TEST.
When the correct answer is negated, the conclusion will be invalidated.

E, negated:
People never drive when it is feasible to walk instead.
In other words:
It is not POSSIBLE for anyone currently driving to walk instead.
Implication:
No one currently driving can switch to walking, invalidating the conclusion that pollution will be greatly reduced.
Since the negation of E invalidates the conclusion, E is an ASSUMPTION: a statement that MUST BE TRUE for the conclusion to hold.



C, negated:
Walking is not the only feasible alternative to driving that results in a reduction in pollution.
Implication:
There are OTHER WAYS besides walking to reduce pollution.
If anything, this negation HELPS the conclusion that pollution will be greatly reduced.
Since the correct negation must invalidate the conclusion, eliminate C.

At times, it’s good to step away from the argument and think about what is really going on and what the author is trying to say.

The negation test is a fantastic way to get you to think in these terms, but mistakes made when creating the negated form of the answer choice can lead to picking the wrong choice.

Basically, the author is saying we can reduce pollution by having people follow this course of action. If people choose to walk rather than choose to drive, we will reduce the pollution.

How does the author think this will happen?

The author uses the fact that whenever a person chooses to walk instead of drive, there is one fewer car on the road creating pollution. Therefore, if we get people to walk whenever it is possible for them to do so (instead of driving), then we will have reduced pollution.

There is always a “jump” made by the author from the facts to the conclusion.

In order for this explicit fact to support the claim that pollution will be reduced, it must be true (in the author’s mind) that cars will be removed from the road when ppl choose to walk.
The only way the claim is supported by the facts is if cars (which emit pollution) are actually removed from the road when people choose to walk.

-C- “Walking is the only feasible alternative to driving that results in a reduction in pollution.”

To get from the facts to the conclusion, is the author required to believe that walking is the ONLY feasible alternative that results in a reduction in pollution?

When a person says if we do this one thing X, then this other thing Y can happen, she’s not worried about whether there are other things that can lead to Y occurring. The focus is just on whether doing X can get Y to happen.


Similarly, in this argument, the author is making the claim that if people choose to walk, there will be a reduction in pollution. She believes choosing to walk instead of drive is one way to get to that reduction. If there are other feasible alternatives to walking, this fact does not impact whether choosing to walk will lead to the reduction.

There could be dozens of alternatives and the author’s claim could still be correct. It wouldn’t matter. When people choose to walk instead of drive, a car is removed. And if enough of these cars are removed, the reduction in pollution can still occur.

Thus C is not a REQUIRED assumption.

-E- “People sometimes drive when it is feasible to walk instead.”

In order to get from the fact of ppl choosing to walk instead of drive to the conclusion that pollution will be reduced, it is required that cars come off the road when ppl choose to walk. After all, this is the mechanism that the author believes will result in less pollution. She believes that each time a person chooses to walk, there is one car removed from the road.

In order for the premise to support the conclusion, it has to be the case that some ppl actually drive when they could feasibly walk instead. Otherwise, there would be no one driving a car on the road right now who could feasibly choose to walk.....and no ADDITIONAL cars would be taken off the road by following the author’s suggestion.

In such a case, all the people who could feasibly choose to walk are already not driving. There are no other cars that can be taken off the road, thereby reducing pollution.

Therefore, the author must assume that there are people who sometimes drive when it is possible for them to walk instead.

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