Sam: During recessions, unemployment typically rises. Thus, air pollut

Question

Sam: During recessions, unemployment typically rises. Thus, air pollution due to automobile exhaust decreases during a recession, since fewer people com-mute in cars to jobs and so cars emitting pollutants into the air are used less.

Felipe: Why would you think that air pollution would decrease? During a recession, fewer people can afford to buy new cars, and cars tend to emit more pollutants as they get older.

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

A. People who have never been employed drive no less frequently during a recession than they would otherwise'

B. Most air pollution is caused by automobile exhaust emitted by cars used by people commuting to jobs.

C. most people who are employed do not use any form of public transportation to commute to their jobs.

D. During a recession, decreases in the use of cars resulting from reductions in commuting to jobs are not offset by increased use of cars for other reasons.

E. During a recession, a higher proportion of people who commute in cars to their jobs lose those jobs than do people who do not use cars to commute to their jobs.

Gerry20 · Answer

yogesh610  - C is wrong because negating it would give you -> lesser than 50 % of people who are employed do not use any form of public transportation to commute to their Jobs.

This answer choice might weaken but does not necessarily shatter the conclusion as negating option D does.

CR Questions that are tough boil down to picking the relatively better answer choice and in this case it is undoubtedly answer choice D.

Hope this helps!

ankujgupta · Answer

Even though I got the correct answer, still want to verify my reasoning.
A-> This was difficult to eliminate. If people who have never been employed, start to drive less than pollution might decrease. But I thought that it is talking about unemployed people and not those who have lost jobs in recession. So eliminated it
B-> Not concerned about what causes most air pollution
C-> Kept on hold. Might be an assumption
D-> This is better than C. If it is offset then pollution will not decrease. 
E-> Irrelevant

abhimahna · Answer

Sam is saying Due to more unemployment, car usage would be less. As the question talks about what Sam is assuming, we don't even need to look for someone else.

So, if he is saying cars won't be used , he is assuming that people who got free will not go for outing with friends/families or other reasons.

Only option that talks about this is D. Hence, the correct answer.

warriorguy · Answer

There is a typo in your explanation. I believe he assumed that due to recession, fewer cars will be on the road.

My reasons as below:

A : People who have never been employed drive no less frequently during a recession than they would otherwise' -  His assumption lies on people affected by recession. It is not concerned with one type (never been employed).

B: Most air pollution is caused by automobile exhaust emitted by cars used by people commuting to jobs. -  His assumption is air pollution will decrease. Most is extreme here.

C: most people who are employed do not use any form of public transportation to commute to their jobs. -  I felt his assumption was that people will resort to using public transportation. So this one is not correct.

D: During a recession, decreases in the use of cars resulting from reductions in commuting to jobs are not offset by increased use of cars for other reasons. -  This one is correct. He doesn't feel any other factor will cause an increase in number of cars on the road. Negating this one affects the conclusion.

During a recession, decreases in the use of cars resulting from reductions in commuting to jobs are offset by increased use of cars for other reasons. If so, then pollution resulting from exhuast gases will not decrease. Conclusion is hurt.

E: During a recession, a higher proportion of people who commute in cars to their jobs lose those jobs than do people who do not use cars to commute to their jobs.

I felt this one is a contender too. But it could be that people don't loose their jobs but would still like to save during recession and opt for public transportation.

Let me know if you see any fault in the reasoning.

TheMechanic · Answer

Good question. Was stuck between B and D but chose D after investing close to 3mins in the question.

B is out because, it impacts the supporting premise of Sam's argument, not his conclusion. The conclusion of Sam's argument is: 
 Thus, air pollution due to automobile exhaust decreases during a recession  . Option B also brings in   magnitude   of Pollution done by cars, that cannot be inferred from Sam's arguments. Hence B is out and D remains.

GMATNinja · Answer

Even if most people who are employed DO use  some  form of public transportation to commute to their jobs, we don't know if those people also drive during their commute (i.e. they might drive the first half of the distance and then take a train or bus the second half). Negating choice (C)  might  weaken the argument, but the argument does not depend on the assumption in choice (C).

rbramkumar · Answer

Sam: During recessions, unemployment typically rises. Thus, air pollution due to automobile exhaust decreases during a recession, since fewer people com-mute in cars to jobs and so cars emitting pollutants into the air are used less.

Here is the core of Sam's argument:

Premise:  Fewer people commute to jobs in car => Less pollutants in air
 Conclusion:  Air Pollution  due to automobile exhaust  decreases

A : People who have never been employed drive no less frequently during a recession than they would otherwise'
 Not the relevant population - we are not interested in the people who've never been employed. The premise talks about people who become unemployed

B: Most air pollution is caused by automobile exhaust emitted by cars used by people commuting to jobs.
 Doesn't matter what contributes most to air pollution. Argument conclusion already refers only to air pollution caused by automobile exhaust. I kinda missed it the first time too, but the term "due to automobile exhaust" is important. 
 
C: most people who are employed do not use any form of public transportation to commute to their jobs.
 Close one - yes this an assumption, but there is a chance that some of them (who'll lose their jobs later) did use their cars. Let's keep this one in for now.

D: During a recession, decreases in the use of cars resulting from reductions in commuting to jobs are not offset by increased use of cars for other reasons.
 Much better of an assumption - directly involves the terms in the conclusion - i.e., the direction of air pollution (increase/decrease). Better assumption than C.

E: During a recession, a higher proportion of people who commute in cars to their jobs lose those jobs than do people who do not use cars to commute to their jobs
 Initially, this does seem like a good choice. However, this is an irrelevant comparison. Of the people who lost their jobs, the proportion(who drove cars to work) > proportion(don't drive cars to work). Whatever the value of proportion(who drove cars to work) is, it will result in lesser air pollution. Not a super critical assumption.

(D)

MasteringGMAT · Answer

The assumption on which Sam's argument depends is:

D. During a recession, decreases in the use of cars resulting from reductions in commuting to jobs are not offset by increased use of cars for other reasons.

Sam's argument is based on the premise that during recessions, unemployment rises and people commute in cars to jobs less frequently. As a result, cars emitting pollutants into the air are used less frequently, which should lead to a decrease in air pollution due to automobile exhaust. However, this argument depends on the assumption that the decreases in the use of cars resulting from reductions in commuting to jobs are not offset by increased use of cars for other reasons.

If there is a significant increase in the use of cars for other reasons during a recession, such as increased travel for leisure or errands, it could offset the decrease in the use of cars for commuting and result in no net decrease in air pollution due to automobile exhaust. Therefore, the assumption that the decreases in the use of cars resulting from reductions in commuting to jobs are not offset by increased use of cars for other reasons is necessary for Sam's argument to hold.

desertEagle · Answer

E is wrong because the proportion of people who commute in car do not matter. Suppose, there are 100 employees. 50 were laid off. Of these 50, only 2 had cars, ie around 4% which is very less. But still there will be some decrease in pollution. So, this cannot be assumption

unraveled · Answer

Sam: During recessions, unemployment typically rises. Thus, air pollution due to automobile exhaust decreases during a recession, since fewer people com-mute in cars to jobs and so cars emitting pollutants into the air are used less.

Felipe: Why would you think that air pollution would decrease? During a recession, fewer people can afford to buy new cars, and cars tend to emit more pollutants as they get older.

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

A.  People who have never been employed  drive no less frequently during a recession than they would otherwise' - WRONG. Irrelevant.

B.  Most air pollution is caused  by automobile exhaust emitted by cars used by people commuting to jobs. - WRONG. "most air pollution" does not equates to "air pollution due to automobile exhaust". Latter is a subset of former.

C. most people who are employed  do not use any form of public transportation  to commute to their jobs. - WRONG. Even if they use it doesn't matter since they may pool or opt other ways to travel. It does look enticing at first but loses out to D.

D. During a recession, decreases in the  use of cars resulting from reductions in commuting  to jobs are  not offset by increased use of cars for other reasons . - CORRECT. If it's offset then Sam's argument falls apart.

E. During a recession,  a higher proportion  of people who commute in cars to their jobs lose those jobs  than  do people who do not use cars to commute to their jobs - WRONG. Irrelevant.

A bit odd type of question stem for such a passage since Felipe's argument is not at all required. Just to confuse or waste time may be.
Only C and D stand a chance.

Answer D.

ncr5982 · Answer

Can you explain option D in simple terms.

egmat · Answer

ncr5982  Here's what  D  is really saying:

"During a recession, the decrease in car use from people NOT commuting to jobs is not canceled out by people using cars MORE for other reasons (like errands, job hunting, leisure)."

Or even simpler:
 "People don't start driving MORE for other purposes to make up for driving LESS to work."

Why This Matters to Sam's Argument

Sam concludes that pollution  decreases  because fewer people commute by car during recessions.

But here's the potential problem: What if unemployed people start using their cars a lot more for other things - running errands during the day, driving around looking for jobs, going out more since they have free time? Then total car use might stay the same or even  increase , and pollution wouldn't decrease at all.

Sam  must assume  this doesn't happen - that the reduction in commuting isn't  "offset"  (canceled out) by increases in other types of car use.

Hope this helps!

Sam: During recessions, unemployment typically rises. Thus, air pollut

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Sam: During recessions, unemployment typically rises. Thus, air pollut

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