If the majority of the residents of the apartment

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If the majority of the residents of the apartment complex complain that their apartments are infested with ants, then the management of the complex will have to engage the services of an exterminator. But the majority of the residents of the complex indicate that their apartments are virtually free of ants. Therefore, the management of the complex will not have to engage the services of an exterminator.
Which one of the following arguments contains a flawed pattern of reasoning parallel to that contained in the argument above?
(A) A theater will be constructed in the fall if funds collected are at least sufficient to cover its cost. To date, the funds collected exceed the theater’s cost, so the theater will be constructed in the fall.
(B) The number of flights operated by the airlines cannot be reduced unless the airlines can collect higher airfares. But people will not pay higher airfares, so it is not the case that the number of flights will be reduced.
(C) In order for the company to start the proposed building project, both the town council and the mayor must approve. Since the mayor has already approved, the building project will be started soon.
(D) Most employees will attend the company picnic if the entertainment committee is successful in getting a certain band to play at the picnic. But that band will be out of the country on the day of the picnic, so it is not true that most employees will attend.
(E) Either the school’s principal or two-thirds of the parent council must approve a change in the school dress code in order for the code to be changed. Since the principal will not approve a change in the dress code, the code will not be changed.

Can some expert explain it logically?


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by EconomistGMATTutor » Wed Oct 18, 2017 12:50 pm
The conclusion: Therefore, the management of the complex will not have to engage the services of an exterminator.

The evidence: 1) If the majority of the residents complain that their apartments are infested with ants, then the management will engage the services of an exterminator. 2) The majority of the residents of the complex indicate that their apartments are virtually free of ants.

This is an if-then argument. If they complain, the exterminator comes. This DOES NOT allow us to conclude what would happen if they don't complain. Maybe the exterminator comes if only one person complains a lot. Or maybe the exterminator comes every 3 months. Who knows? We don't.

Here's another way to look at it. Given a statement in the form of If A, then B, you cannot conclude If Not A, then Not B. We can't say If Not A . . . anything. You CAN conclude If Not B, then Not A. For this argument, we can say that IF the exterminator did NOT come, THEN the residents did NOT complain.

So which choice makes the same mistake of saying "If A, then B means that we can say If NOT A, then NOT B? That would be Choice D. This choice says "IF the band plays THEN most employees will attend" and then concludes IF the band does not play, THEN the employees will not attend. That's the same mistake, so it's the correct answer.

I'm available if you'd like any follow up.
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