Critical Reasoning

richachampion wrote: I think the process to eliminate E should be like this -

Attempting to make up the tax revenue lost by raising tax rates is not feasible since higher tax rates would cause even more residents to leave.

causal argument = Increase the Tax revenue by increasing tax will cause more populating decline.

X, THEREFORE Y situation.
But what E is trying to say IS

Y, THEREFORE X

This can't be true. Is my approach correct?
In Inference question, if the stimulus has given X, THEREFORE Y then we can't infer.
Y, THEREFORE X.

Yes, your reasoning is correct as I understand it. We can't reverse causal reasoning in this way.
E.g. Sharply increasing ice cream consumption will cause weight gain. Therefore, lowering ice cream consumption will cause weight loss.

Just because increased ice cream causes increased weight gain does not mean that decreased ice cream would cause weight LOSS... unless ice cream was the ONLY factor in weight gain or loss.

In this case, residents are already leaving the city (we don't know the reason, but it may not be all about taxes). Increasing taxes could cause more people to leave the city more quickly, but that doesn't mean that lowering taxes will cause them to come BACK.

If the language of answer choice E were more hedging (the city "... may be able to make up some of the lost...") rather than declarative ("can make up..."), then it might have been more justifiable. As written, we certainly can't infer E.

richachampion wrote: I also feel that Option A is not the best option, but the last devil.

(A) If in a city with a sharply declining population, police protection and water line maintenance do not deteriorate, some other service previously provided by the city will deteriorate or be eliminated.

The Part in red doesn't make this a completely perfect answer, but the least devil. We can't actually deduce the part in red because in that we will be governed by the real world thinking. because the part in red is actually a real world thinking, but not something that is explicitly stated in the stimulus.

I tend to agree with you. The argument actually makes A mostly justifiable, but the language is a bit too extreme.

The logic of the argument:
- population decline = tax revenue decline
- tax revenue pays for police protection and maintenance of water lines
- the area to be policed and the number and length of the water lines to be maintained do not decrease
- attempting to make up the tax revenue lost by raising tax rates is not feasible

Thus, one of three things must happen:
1) funding for police and water lines will decrease, since overall revenues decrease
2) if funding for police or water lines stays consistent or increases, then funding for something else must decrease
3) some other revenue source must be discovered to pay for all services at the same rate

I think the one way in which answer choice A is faulty is that it neglects option 3 here. If there were some other potential revenue source besides tax revenue, A would not necessarily be inferable.

If #3 were not an option, though, then either #1 or #2 would have to be true. Answer choice A essentially says the same thing as option 2 here... but with slightly stronger wording. What if other services were wasting money? Maybe they could be trimmed down / scaled back without "deteriorating," which is too strong/negative a word. I would feel a lot better about A if it had said "will receive decreased funding" or some such.

However, if we look back at the question, it reads:
The information given most strongly supports which of the following general claims?

Generally we would interpret this as "what is inferable?" However, it is not quite as exact as a question that asks, "Based on the information above, which of the following must be true?"

Sometimes, as you say, we have to pick the least-worst option!