Because of extreme congestion in the city of Nobi, it typically takes

Question

Because of extreme congestion in the city of Nobi, it typically takes close to one hour to commute at rush hour to the downtown business area by car from the neighboring suburbs that are only ten to fifteen miles away. Recently, the city installed separate bus lanes that connect these suburbs to the downtown area and that allow buses to move unimpeded during rush hour. With these new lanes, commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time than they could previously by driving their cars.

Which of the following would be most important to know in evaluating the argument above?

Which of the following would be most important to know in evaluating the argument above?

A Whether a large percentage of commuters drive to the downtown area at times other than rush hour.
B Whether a large percentage of commuters use means other than driving to commute to the downtown area during rush hour.
C Whether the buses have frequent departure times during rush hour.
D Whether the buses make frequent stops when traveling between the suburbs and the downtown area during rush hour.
E Whether the buses used in the new separate lanes are similar to other buses used.

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VivekSri · Accepted Answer

Let us have a detailed explanation on how this type of question we solve.

Evaluate Argument is a special type of question which can strengthen or weaken the conclusion on the answer. If after evaluating, your ans is No, it strengthens the conclusion and if after evaluating, your answer is Yes, it weakens the conclusion, then this is your answer.

Now, what your premise is saying -> Due to congestion for 10-15 miles it takes one hour to travel.
What City is doing -> The city installed separate bus lanes that connect these suburbs to the downtown area and that allow buses to move unimpeded during rush hour. 
Conclusion: Commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time than they could previously by driving their cars.
Now what we have to find is one option whose Boolean ans(Yes/No) will either strengthen/Weaken the conclusion.

Let us start the option elimination:

A Whether a large percentage of commuters drive to the downtown area at times other than rush hour.
  Totally irrelevant, I wont even do the Boolean test for this, If yes may be 70% of the people travel other than the rush hour, will it impact on conclusion. Read the conclusion again, we have to hit on the time saving.  
B Whether a large percentage of commuters use means other than driving to commute to the downtown area during rush hour. 
 Again irrelevant, what people are using now is no where related, author is saying after these separate lane people will use bus and it will take less time. 
C Whether the buses have frequent departure times during rush hour.
  C is a trap here, Let us say yes, the buses have frequent departure times,   so can we say Commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time?   May be they can reach in less time or may be they cant reach in less time. 
  Now negate this, the bus have not frequent departue times during rush hour   can we say that Commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time?  
No right? May be yes or may be not. so this option neither strengthens the conclusion nor weakens it. 
D Whether the buses make frequent stops when traveling between the suburbs and the downtown area during rush hour.
  Let us say yes, the buses have frequent stops when travelling, so can we say Commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time? Definitely we can say no, commuter will not able to save time. This is weakening the conclusion. 
Let us say no, the buses have no frequent stop when travelling.so can we say Commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time? Definitely we can say Yes, commuter will now able to save time. This is strengthening the conclusion.   
E Whether the buses used in the new separate lanes are similar to other buses used.
Totally irrelevant. So OOS.

sood1596 · Answer

IMO D.

because if the buses make too many stops, it could significantly slow down the commute, making them less attractive than driving.

Confused between C and D

VivekSri · Answer

I will go with D as I think yes the bus will have no congestion but if it has frequent stops then the time saved in congestion will go in stops.

For example,
Previously 
if people used to take 60 mins for ten to 15 miles
Now,
Drive time is only 30 min
Stoppage time(Take an example 3 min every stop and there are 10 stops) - 30 min
so 60 min.
So IMO D

cosmoboiAB · Answer

Let us sit back focus on the conclusion (last line) for a bit:

With these new lanes, commuters from the suburbs (1. specifically this region) will now be able to use the bus to reach the downtown area (no other area considered) during rush hour (2. no other time considered) in considerably less time (3. time taken is the parameter in evaluation) than they could previously by driving their cars (4. no other means of travel considered).

A Whether a large percentage of commuters drive to the downtown area at times other than rush hour. 
Straight away from point 2, we know only rush hour is considered.  Eliminate

B Whether a large percentage of commuters use means other than driving to commute to the downtown area during rush hour. 
From point 4, we know only driving by cars is considered.  Eliminate

C Whether the buses have frequent departure times during rush hour. 
Let's say the buses departure every 5 minutes. Then almost everyone can avail this facility regardless their work timings.
Let's say there is only one departure time for the whole day. Then again, at least some commuters can possible avail this facility. (It doesn't say all does it?)
Then again, I am not sure waiting for the departure time is considered in commute time.

This option could possibly help evaluate the argument, but very weakly.  I would go with this if I don't find a better argument.
 
 D Whether the buses make frequent stops when traveling between the suburbs and the downtown area during rush hour. 
We can see that the number of stops the bus makes, will directly affect the time it takes to reach the downtown area.
And from point 3, we know that is exactly what's under evaluation.  Solid option

E Whether the buses used in the new separate lanes are similar to other buses used.

Let's say the buses used are similar. Do we know whether the buses used are fast or slow? No idea
Let's say they are not similar. Do we know whether the buses in the lanes are faster/slower the ones used outside? No idea
Moreover, the comparison in between the buses in the lanes and the cars.  Eliminate

Answer: (D) 
.

Bunuel · Answer

VERITAS PREP OFFICIAL SOLUTION:

In this argument, the conclusion states that people will be able to get downtown in less time by bus than by driving. What is the reason given for this conclusion? That new bus lanes have been made which allow buses to move unimpeded through congested areas. As in any useful to evaluate question, you should attack this line of reasoning and consider what assumptions or flaws are inherent in the argument. At its heart, this argument assumes that because buses can move unimpeded in the new lanes, they will travel the distance faster than cars that do not have special lanes. But what if the buses are incredibly slow for other reasons? What if they have to stop every quarter mile for time consuming drop-offs and pick-ups? In analyzing the answer choices, you are looking for some piece of information relating to this assumption.

For (A), what percentage of commuters drive outside of rush hour is unimportant as this argument is only concerned with the time it takes at rush hour.

Similarly for (B), the argument only makes a comparison between buses and driving so other means of travel are not important.

(C) is tricky as it seems like it might matter but this argument is only concerned with the time it takes to get from point A to point B at rush hour. Whether the bus leaves every 5 minutes or every 30 minutes has no impact on the conclusion as it does not change how long it would take.

(D) addresses exactly the assumption discussed earlier and is thus correct. If the bus makes frequent stops then it might actually take longer than driving a car, greatly weakening the conclusion.

For (E) the similarity of the buses does nothing to address the issue of time compared to driving so is not relevant.

Correct answer is (D).

billlyjoehbs · Answer

KarishmaB

Can you please help me understand why D is better than C.

The question stem "With these new lanes, commuters from the suburbs  will now be able  to use the bus to reach the downtown area during rush hour in considerably less time than they could previously by driving their cars.

Wouldn't the frequency of departure times play a key role? if there's only one bus, the commuter may end up waiting the entire time during which he could have travelled to the destination in car despite traffic. Alternatively, if the frequency is large enough, this could be a viable travel route.

The only reason I eliminated option D is that despite frequent stops, you can still move quickly via bus than in cars. So not a strong enough option.

pls help!
thanks

srik410 · Answer

Had the same logic and went for D. In hindsight, the conclusion said on the lines of 
when the bus is used -> it takes significantly less time (A->B)

Which I think translates to if the bus is used then always it will take significantly less time. 
This can be refuted with A -> not B. D tackles this perfectly(even though they are used, they take significantly more time if they have frequent stops)

Note that A->B cannot be refuted with not A(which is saying bus cannot be used).

Pranavsawant · Answer

This is such a bad question. Even if it makes frequent stops there is absolutely no guarantee that it will not take shorter time. Maybe it still takes you to downtown in 30-35 mins after all the "frequent" stops. Such ambiguous reasoning I believe won't be tested on the GMAT. Moreover, option C is more compelling. If the buses aren't frequent enough, everyone will have to catch the bus at the same time. This leads to two scenarios

1) People who will the bus will have to use their car 
2) Buses will be so crowded that people might have a tendency to use their private vehicles or other means.

However, if it is frequent, such instances will most likely be eliminated. I know that this does involve some asusmptions like population, seating capacity etc but all of the options are equally poor. Option D involves making far worse assumptions which is a big NO-GO

DmitryFarberMPrep · Answer

Careful here. First, it's extremely important that we are not looking for something that proves or disproves the argument. That is almost never the task. We are just looking for an answer that helps us better evaluate whether the conclusion is likely to be correct. This often involves addressing an assumption. In this case, the author has assumed that the unimpeded buses will take less than an hour to arrive. This involves assuming that the buses don't move very slowly or stop a great deal. If they DO move slowly and/or stop, then the conclusion does not clearly follow from the premises. That doesn't mean it's false; it just means we now have reason to doubt it. If they DO NOT move slowly or stop, then it seems much more reasonable to conclude that the time will be shorter than an hour, and thus that commuters can reduce their travel time by taking the bus. So we can definitively say that D is helpful in evaluating the argument.

I understand your concern about C. I predicted something along the same lines myself. I wondered if there was some way that TOTAL travel time might stay the same or go up, perhaps because of travel time to the bus, waiting for the bus, transferring, etc. But notice that C doesn't address any of that. It only addresses whether buses arrive frequently. This doesn't tell us anything about how long people will take overall, unless they are in the habit of simply showing up and waiting for a bus without regard to schedule, in which case I'd be inclined to agree with Veritas and not count that as travel time. Additionally, if the buses are NOT frequent, that doesn't necessarily hurt the argument. As long as there is at least one bus that travels during rush hour, and as long as that bus takes well under an hour to make the full trip, then people will indeed have a faster option than using their cars. That is, unless there is some OTHER obstacle, such as the overcrowding you thought of or the travel to the stop that I thought of. But again, C does nothing to address those issues at all.

Another important point here is that we can't add our own objections and assume what affect a given answer would have on them. We actually have no idea whether infrequent buses will force people back to their cars. After all, we have no information about the number of commuters, the size of the buses, etc. We also know nothing about whether people would rather drive slowly in their cars than endure a crowded bus. All of this would have to be spelled out clearly in order for us to make the connection you talk about for C. As I outlined above, answer choice D requires no assumptions on our part at all.

gullyboy09 · Answer

Hi  MartyMurray , can you please help me with option C here?

part of conclusion is - "..commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour", but if frequency of bus is very low, then commuters might not be able to use the bus to reach the downtown areas. (For example if there is only one bus that travels, then IMO it might not solve the issue).

guddo · Answer

Because of extreme congestion in the city of Nobi, it typically takes close to one hour to commute at rush hour to the downtown business area by car from the neighboring suburbs that are only ten to fifteen miles away. Recently, the city installed separate bus lanes that connect these suburbs to the downtown area and that allow buses to move unimpeded during rush hour. With these new lanes, commuters from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time than they could previously by driving their cars.

Which of the following would be most important to know in evaluating the argument above?

Which of the following would be most important to know in evaluating the argument above?

The argument says that because buses now have separate lanes and can avoid traffic, commuting by bus during rush hour will be much faster than commuting by car used to be.  The key assumption  is that  the overall bus trip  will in fact be shorter, not just the parts where the bus is moving freely in its lane.

A. Whether a large percentage of commuters drive to the downtown area at times other than rush hour.

This does not matter much. The argument is specifically about rush-hour travel.

B. Whether a large percentage of commuters use means other than driving to commute to the downtown area during rush hour.

This is also not important. The argument is about whether the new bus option is faster than driving, not about how many people already use other methods.

C. Whether the buses have frequent departure times during rush hour.

This matters somewhat, but it is not the most important point. Departure frequency affects convenience and waiting time, but the argument mainly depends on whether the bus trip itself is actually faster.

D. Whether the buses make frequent stops when traveling between the suburbs and the downtown area during rush hour.

This is the best answer. Even if buses move unimpeded in separate lanes, frequent stops could still make the trip long. So this directly affects whether bus travel will really be considerably faster than driving.

E. Whether the buses used in the new separate lanes are similar to other buses used.

This is irrelevant. What matters is travel time, not whether the buses are similar to others.

Answer: (D)

MartyMurray · Answer

(C) is not really a fair answer choice. As you've basically suggested, if the departures are "frequent," then we have confirmation that the frequency of the buses is not "very low," meaning that the buses have capacity to carry many commuters. So, (C) in way helps to confirm that commuters will be able to use the bus to reach the downtown area during rush hour in considerably less time than they could previously.

So, this question is not optimally designed.

At the same time, we can get this question correct by seeing that the conclusion is the following:

With these new lanes,  commuters  from the suburbs will now be able to use the bus to reach the downtown area during rush hour in considerably less time than they could previously by driving their cars.

What we can notice is that the conclusion is not about "all commuters" or "many commuters." Rather, it is about "commuters."

So, we can eliminate (C) and choose (D) by seeing that, regardless of the frequency of the buses, at least some "commuters" will be able to use the bus to travel more quickly than they could previously, meaning that, regardless of whether the answer to (C) is "yes" or "no," the conclusion holds.

Because of extreme congestion in the city of Nobi, it typically takes

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