Hi Aditya8062,
You have raised primarily two concerns: the first of which is a very common doubt faced by the students. Let’s tackle your concerns one by one.
aditya8062 wrote:
the options C has to make some assumptions before it is credited as answer
how do we know what is more convenient ? i mean u cant just randomly assume that a gasoline car is more convenient. !! who knows? an elderly man might hate noise and gasoline cars make lot of noise as compared to electric cars !!
Common doubt: Can a weakener make assumptions to weaken the conclusion?
Answer: Yes. In most of the
OG questions, weakeners don’t disprove the conclusion by themselves. They need to make certain assumptions, in order to invalidate the conclusion.
For example: Consider the below GMAT Prep question:
According to the Tristate Transportation Authority, making certain improvements to the main commuter rail line would increase ridership dramatically. The authority plans to finance these improvements over the course of five years by raising automobile tolls on the two high-way bridges along the route the rail line serves. Although the proposed improvements are indeed needed, the authority’s plan for securing the necessary funds should be rejected because it would unfairly force drivers to absorb the entire cost of something from which they receive no benefit.
Which of the following, if true, would cast the most doubt on the effectiveness of the authority’s plan to
finance the proposed improvements by increasing bridge tolls?
(A) Before the authority increases tolls on any of the area bridges, it is required by law to hold public hearings at which objections to the proposed increase can be raised.
(B) Whenever bridge tolls are increased, the authority must pay a private contractor to adjust the automated toll-collecting machines.
(C) Between the time a proposed toll increase is announced and the time the increase is actually put into effect, many commuters buy more tokens than usual to postpone the effects of the increase.
(D) When tolls were last increased on the two bridges in question, almost 20 percent of the regular commuter traffic switched to a slightly longer alternative route that has since been improved.
(E) The chairman of the authority is a member of the Tristate Automobile Club that has registered strong opposition to the proposed toll increase.
What is the correct answer here?
The answer is Choice D.
Now, one can see that Choice D needs to make a number of assumptions for it to weaken the argument. Two of the assumptions are:
1. The pattern of traffic that was seen last time would be repeated this time also. This assumption is needed since Choice D talks about a pattern in the past and if the past pattern is not expected to be repeated, the choice doesn’t have an impact on the conclusion.
2. The authority needs at least 70%-80% of the current traffic to achieve its financial goals. If this is not true, then even if 20% or 30% of the traffic gets diverted, it won’t have an impact on the plan.
In light of the fact that Choice D needs to make the above assumptions, can we call Choice D incorrect? The answer is No. The reason is that the question stem doesn't ask us to select an answer choice which conclusively breaks down the conclusion. The question stem asks us to select a statement that “casts doubt” on the effective of the plan.
So, after reading Choice D, we don’t really disbelieve in the authority’s plan; we are just less sure of it now. Now, we may need to ask additional questions to get back our belief in the plan?
The same is the case with the given question of Papula country. Option C brings in new information, which says that the priority of retirees is convenience rather than costs. Does it say that gasoline cars are more convenient that electric cars? No. But it brings up a point (convenience), which has not been considered so far. It just makes us little less sure of the plan. Now, we may need to ask certain questions to shore up our belief in the plan.
aditya8062 wrote:
also the question stem never say that the plan
if implemented wud be success or not so the fact is that we can very well question on the possibility of its happening or not happening and that is what B
does it raises question on th first place that plan is very difficult to implemented
i think
Egmat sud rephrase the question stem by saying the plan
if implemented wud blah blah blha....in order to eliminate B as a contender
Consider the above GMAT Prep question again and look at both the question stem and the Option E. The question stem doesn’t say that the plan “if implemented” and Option E does raises a doubt that the plan might not be implemented at all. Is Option E the correct choice? No.
Why?
The reason is that the question stem is talking about the effectiveness of the plan to achieve something and option E is saying that the plan might not be implemented. So, they are actually going in tangential directions. Let’s take below analogy to understand this:
A: Given that we enjoyed our visit to the zoo last time, we should plan to go to zoo this time to make the maximum out of our time.
B: You are wrong. We cannot go to zoo time because the zoo has been closed for public.
Does B weaken A’s conclusion? The answer is No. Because A is not talking about whether going to zoo is possible or not, it is just saying that going there will lead to enjoyment.
Similar is the case with Option E of the GMAT Prep question and Option B of our question.
I hope the above explanation helps in clarifying certain doubts.
aditya8062 wrote:
i guess this argument has been poorly formulated :
It is always easier to point fingers at the quality of the questions but the key to learning is to understand not only why correct choices are correct but also why incorrect choices are so. I would have appreciated your concerns a lot more if you had raised your doubts in a pertinent manner instead of making value judgments about the quality of the question.
Thanks,
Chiranjeev