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C. City logic is the new system will increase vehicle flow through junction by 25%. This leads to the conclusion that the waiting time at red lights will fall by 20%.
The assumption here is, the number of cars will NOT increase due to increase flow. Which is a flaw because people might think, "well traffic is less so I should take the downtown route over other routes".
Why others are wrong?:
A - question doesnt disucss timeline, irrelevant
B - The question doesnt ask what the technical flaws are of the system itself, rather speculative, we have no info if the system will malfunction.
D - we are not being asked to evaluate the percentage quoted, irrelevant
E - cost benefit is irrelevant as the conclusion is hitting a congestion target not whether the investment is financially viable.
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Bunuel
The city of Metropolis aims to reduce morning traffic congestion in the downtown core, defined as the average time spent waiting at red lights, by 20%. To achieve this, the city council has installed a new, highly advanced synchronization system for all traffic lights, an investment that cost $12 million. Since this system can increase the number of vehicles that pass through major intersections every hour by an average of 25%, the city council concludes that the installation of the new system will ensure that the city meets its congestion reduction target.

The argument above is flawed in that it:

(A) fails to establish a clear timeline for when the 20% reduction in congestion is expected to occur.
(B) fails to consider whether the advanced synchronization system will experience mechanical malfunctions or software errors during its initial implementation phase.
(C) assumes that the increased traffic flow through major intersections will not encourage more people to drive to the downtown core.
(D) provides statistical data from a new system but does not compare its performance with the city’s previous, older traffic light system.
(E) does not justify the $12 million investment by showing that the monetary benefits of reducing congestion will exceed the cost of the new system.

 


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A. Timeline is irrelevant. Whether morning traffic congestion will go down by 20% is the concern.
B. Irrelevant. Whether congestion will go down after full implementation is the concern.
C. Correct. The argument ignores the fact that allowing more cars to pass through intersections might encourage more people to drive, resulting in a net increase in the number of vehicles. Hence the traffic congestion may not go down.
D. It does compare the performance of the new system with the older traffic light system (25% increase).
E. Justification of investment is irrelevant.
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conclusion:

traffic flow increases by 25% ->because of which -> waiting time will reduce by 20%

But just because more cars will pass through an instersection that doesnt necessarily mean that it will lead to reduction in waiting time.

A-IRRELEVANT
B- IRRELEVANT
C- people might chose to go downtown and that can increase demand there and it can induce congestion there so the city might not achieve the goal of 20% reduction.
D. IRRELEVANT
E- IRRELEVANT. No talk about financial investments,
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Lets breakdown the passage:

Bunuel
The city of Metropolis aims to reduce morning traffic congestion in the downtown core, defined as the average time spent waiting at red lights, by 20%. To achieve this, the city council has installed a new, highly advanced synchronization system for all traffic lights, an investment that cost $12 million. Since this system can increase the number of vehicles that pass through major intersections every hour by an average of 25%, the city council concludes that the installation of the new system will ensure that the city meets its congestion reduction target.

The Goal: Reduce traffic congestion by 20%
The Plan: Spend 12$ million dollars to get a new system which increases number of vehicles passed at major intersections by 25%
The conclusion: The goal is achieved

Let's go via the process of elimination:
Quote:

(A) fails to establish a clear timeline for when the 20% reduction in congestion is expected to occur.
There is no connection between our goal and timeline, hence, eliminated
Quote:

(B) fails to consider whether the advanced synchronization system will experience mechanical malfunctions or software errors during its initial implementation phase.
Even if the system malfunctions/glitches initially, there is nothing to say that the goal will be disturbed when the system runs fully, hence, eliminated
Quote:

(C) assumes that the increased traffic flow through major intersections will not encourage more people to drive to the downtown core.
Nowhere in the passage is the possibility of the above, reduced traffic time == more number of vehicles, is considered, which may become an issue, keep it
Quote:

(D) provides statistical data from a new system but does not compare its performance with the city’s previous, older traffic light system.
Explicitly mention, hence, we can eliminate this.
Quote:

(E) does not justify the $12 million investment by showing that the monetary benefits of reducing congestion will exceed the cost of the new system.
The goal is to reduce traffic congestion, not justifying our investment, and for that reason, we can eliminate this
Quote:


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We can safely say that (C) is the answer, atleast IMO
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i am going with c.
as total number of car increases and that prevents 20% reduction in wait times
a incorrect as irrelevant
b incorrect as it can be a general risk but doesn't address logical gap
d incorrect fixing old system doesn't fix logical gap of future behaviour
e incorrect irrelevant as it is not about cost benefit concern
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The answer is C.

The stated objective of the City is to reduce average time spent waiting at red lights by 20%. The argument concludes that the city will meet its goal because of the new highly advanced synchronization system. The stated reasoning for this conclusion is that the system is capable of increasing the number of vehicles that pass through intersections by an average of 25%.

Notice that the conclusion does not logically follow from this reasoning; it is equating the 25% increase in vehicles as leading to a direct 20% reduction in time spent waiting at red lights. We need an answer which points out this inconsistency.

A - Knowing when the 20% reduction will occur is not relevant to the city's stated goal. Discard.

B - This is not the reason why the argument is flawed; that consideration is not necessary to the argument.

C - Correct - this points out the disconnect between the capabilities of the new system and the metric for the stated goal.

D - Data compared to the previous system not being provided is not the reason why the argument is flawed.

E - The monetary cost being recouped is not at issue here, the issue is whether the City will achieve the stated objective.
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The correct answer is C.
It's the correct flaw as it assumes that increasing capacity automatically leads to less congestion.
A - irrelevant
B - out of scope
D - irrelevant
E - doesn't address logical gap
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A- timeline is not necessary for conclusion.
B-possible malfunctions are speculative and not the central logic flaw.
C- makes sense because it reduces congestion
D-no performance measure is provided from the argument.
E-The argument is about whether the target will be met, not whether the investment is economically justified.
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C is the correct choice. The statement is flawed on the assumption part here. City council expects that avg. 25%/hr increase in traffic flow will reduce wait time at red signal lights by 20%. The implicit assumption here is that any increase in flow through will not increase traffic volume.

A: Not relevant as timeline doesn't matter here
B: Irrelevant. Because even if it fails at the initial phase, it can still work at later stage
D: Performance comparison with the older traffic light system will not yield anything here. So, not relevant
E: Conversation is not about risk return here. So, a money invested comparison is not a flaw. Moreover, we don't have all the information to do cost benefit analysis as well
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The answer is C

(A) The argument tells the city mayor wants to reduce morning congestion. Eliminate.
(B) Add new facts, such as a malfunction. Never talk about that in the question. Eliminate.
(C) If the people stop driving through there, it will create a flaw for this argument. People should drive there. Answer.
(D) There is a bad comparison. Eliminate.
(E) It is a trap as they talked about the cost, but the city mayor wanted to reduce the traffice, not think about the cost. Eliminate.
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A- The argument actually did not mention timeline but even if they want to achieve 20% reduction after 5 years then also it is okay.. ultimately they will achieve
B- This is irrelevant.. Any device can malfunction.. that does not mean they will not be used.
c- Interesting in the sense-- because smoothening traffic flow due to installation of new device may attract more new drivers and may further aggravate the condition
D- Very very irrelevant
E- This is not even point of contention. cost benefit analysis. It is not done for any business purpose. For ease of city commuters.

Answer should be C
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IMO C

A= Since no of vehicles pass through major intersection will be increased every hour by an avg of 25%, its pretty much providing a timeline. not a flaw
B= whether the system will face malfucntion or not is not a flaw considering the arg scope. We should be concerned if the new system be able to solve the issue mentioned or not
C=Looks good since if traffic flow is increased at intersections, many people might avoid the inetrsection & drive to downtown which will mean the solution is failed.
D=comparing performance with older traffic light system data doesnt determine the flaw with the solution implemented
E= monetery benefit is out of scope
Bunuel
The city of Metropolis aims to reduce morning traffic congestion in the downtown core, defined as the average time spent waiting at red lights, by 20%. To achieve this, the city council has installed a new, highly advanced synchronization system for all traffic lights, an investment that cost $12 million. Since this system can increase the number of vehicles that pass through major intersections every hour by an average of 25%, the city council concludes that the installation of the new system will ensure that the city meets its congestion reduction target.

The argument above is flawed in that it:

(A) fails to establish a clear timeline for when the 20% reduction in congestion is expected to occur.
(B) fails to consider whether the advanced synchronization system will experience mechanical malfunctions or software errors during its initial implementation phase.
(C) assumes that the increased traffic flow through major intersections will not encourage more people to drive to the downtown core.
(D) provides statistical data from a new system but does not compare its performance with the city’s previous, older traffic light system.
(E) does not justify the $12 million investment by showing that the monetary benefits of reducing congestion will exceed the cost of the new system.

 


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for the GMAT World Cup Competition

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When quickly reading the question stem and answer choices we clearly see option (C) standing out.

If the new system encourages more drivers to enter the downtown core, the total volume of cars will increase, meaning the average wait time at red lights might not decrease at all, preventing the city from reaching its 20% target.

Hence correct choice is Option (C)
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There is a lot of information in this but the important ones is the quantifers -
Target = to reduce the Average Time Spent waiting at red lights BY 20%
Solution result = Can increase the number of vehicles pass through EVERY HOUR by an average of 25% - note that it does not say the AVERAGE TIME SPENT is reduced to 20% it only provides solution for more vehicles to be passed. And if the incoming vehicles remain constant then surely it could reduce the Average Time.

A) Clear Timeline is not an issue here. As it says *every hour* and if the vehicles remain constant then it could definitely achieve 20% reduced average time

B) Irrelevant - directly rule out this as it does not talk about anything related to the stimulus

C) This is exactly the potential flaw - what if there would be 100% more vehicles on that route now then how would it reduce the AVERAGE TIME as there are lot more vehicles. At first there were 100 vehicles and then after considering the solution the vehicles reduced to 75 and now there is an increase of 100% and now there are 150 vehicles. So, we now have a bigger Average Time Spent is more than before using the solution - CORRECT

D) It is irrelevant - it does provide statistical data from a new system but it does compare its performance only if the number of cars would be constant or increased to a certain limit.

E) Out of scope - amount of investment has nothing to do with any kind of flaw in this option.

Why number of vehicles shall be constant or could be increased to a certain limit for the Solution situation given:

Before Solution
Average Time Spent = 100s and Number of Vehicles = 100

After Solution
Number of vehicles = 75. So now there is a possibility the red light would not last longer because the traffic is cleared quicker than situation of before implementing solution.
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Here the argument is that with the new system, the city will achieve its desired target of reducing its morning traffic congestion by 20%.

A) There is no mention of timeline at all for the target to be achieved, but there is also no mention of the timeline that the new system will take to exhibit this change. However, the phrase implies that this change will be pretty immediate as the system is synced across all lights and will start working instantly. Therefore, not a strong option.

B) Even if the system faces failures or software errors in 'implementation' phase, these will eventually be worked around and the system will start working at optimal capacity. Option does not hold up.
Since the phrase does not indicate that this reduction needs to happen immediately, this does not weaken the argument.

C) Increased traffic can be a problem in achieving this goal. Assume the new system reduces congestion by 25%, but due to less congestion, 15% more vehicles see it as a viable option to drive in downtown core. This immediately negates the benefits of the system and can stop the city from achieving its target! We hold onto this option.

D) Actually, the phrase literally states that the new system will increase the number of vehicles that pass through major intersections by 25%. Which is a comparison with how many vehicles could pass under the old system. Invalid option.

E) In no form does the phrase position this problem as a monetary problem. It is a traffic and congestion issue, hence attaching a monetary lens introduces a new variant that is not stated in any form. Invalid option.

Option that holds up the best- C
Answer- C
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The city official presumes that by installing the advanced sync system the congestion problem will be resolve. How ? the reason provided is that the system would enable an INCREASE in the number of vehicles that can pass through the MAJOR intersections every hour (increase by 25%). What if because the advanced system is in place, people who would normally avoid the major intersections because of congestion also feel like travelling through it ? It could bloat up the congestion problem even more.

(A) It doesn't matter what the time line is. Whether the reduction happens in a few weeks or a few months is not the question. Effectiveness of the sync system is the question.
(B) Even if there are mechanical issues in the initial implementation. It doesnt weaken the argument. The argument can still stand, hence not a flaw.
(C) Correct: More people think ---> oh its now that the new system is in place lets go through the major intersections. That could swell up the traffic problem.
(D) Comparison with previous light systems is out of scope.
(E) The cost is just mentioned as a fact, its not the point of contention. Certainly not the flaw in the argument



Bunuel
The city of Metropolis aims to reduce morning traffic congestion in the downtown core, defined as the average time spent waiting at red lights, by 20%. To achieve this, the city council has installed a new, highly advanced synchronization system for all traffic lights, an investment that cost $12 million. Since this system can increase the number of vehicles that pass through major intersections every hour by an average of 25%, the city council concludes that the installation of the new system will ensure that the city meets its congestion reduction target.

The argument above is flawed in that it:

(A) fails to establish a clear timeline for when the 20% reduction in congestion is expected to occur.
(B) fails to consider whether the advanced synchronization system will experience mechanical malfunctions or software errors during its initial implementation phase.
(C) assumes that the increased traffic flow through major intersections will not encourage more people to drive to the downtown core.
(D) provides statistical data from a new system but does not compare its performance with the city’s previous, older traffic light system.
(E) does not justify the $12 million investment by showing that the monetary benefits of reducing congestion will exceed the cost of the new system.

 


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I used a answer choice elimination approach for this one. Goal here is to reduce morning congestion by 20%. For that, a new sync system has been put in place. That system increases number of passing vehicles from major intersections by 25% and with this data point, city council thinks that the congestion problem will be solved.

A. Timeline of effect of the new system is not a concern. Whether it will solve the congestion problem or not is the question. Out of scope.
B. Even if there are some initial issues, the system might prove effective in the mid to long term. Does not tell us if the issue will be solved with the new system.
D. We are not concerned how old system performed. Whether the new system will be able to solve the issue prospectively cannot be answered with stats from older system.
E. Justification of investment or ROI is out of scope
C. Best of the lot. Even if number of vehicles passing at current volumes is increased by 25% but if, looking at the speed of traffic, 30% higher number of people start travelling by car, the newly implemented system will fail. THIS IS THE ANSWER AS PER ME.
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