reasoning question

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reasoning question

Postby tequilawine » Sun Mar 22, 2015 6:32 pm

can anyone help me with this?

if the prosecutor wanted to charge frank with embezzlement, then frank would already be indicted. but frank has not been indicteted. so clearly frank is not an embezzler.
the flawed pattern of reasoning exhibited by which one of the following is most similar to that exhibited by the argument above?
a if rosita knew that her 9;00 appointment would cancel, she would not come in to work until 10. she did not come in until 10. so she must have known her 9;00 appointment would cancel.

c if makoto believed that he left the oven on, he would rush home. But he is still at work. So obviously he did not leave the oven on.

The right answer is C. but I don't know what's wrong with A.

Thank you


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Joined: Wed Jan 28, 2015 1:40 pm

Re: reasoning question

Postby trvr » Sun Mar 22, 2015 6:58 pm


If prosecutor wanted to charge Frank with Embezzlement --> Frank would already be indicted

Since Frank has not been indicted, he is not an embezzler.

Flaw: The fact that Frank has not been indicted only indicates that the prosecutor did not want to charge frank w/ embezzlement; it says nothing about his actually being an embezzler.
Answer choice A:

If Rosita knew her 9:00 would cancel --> Rosita would not come into work until 10

Rosita did not come into work until 10, so she must have known her 9:00 would cancel.

Flaw: Confuses the necessary condition for a sufficient condition. The stimulus does not do this. The stimulus takes its own necessary condition and uses it as a sufficient condition for something not within the original conditional statement (we don't know if Frank actually is an embezzler or not, we just know that the prosecutor doesn't want to charge him).

Choice C:

If Makoto believed he left the oven on --> he would rush home

Makoto has not rushed home, so he did not leave the oven on.

Flaw: The fact that Makoto has not rushed home indicates only that Makoto does not believe he left the oven on; it says nothing about whether the oven is actually on.

Hope this helps!


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Joined: Thu Mar 12, 2015 11:19 pm

Re: reasoning question

Postby queerqueg » Sun Mar 22, 2015 7:06 pm

In A, knowing that the appointment would cancel would surely lead to arriving at 10. This doesn't work the other way around though. If all we know is that she came in at 10, then there are plenty of other explanations.

In diagram form, A → B must be true, but B → A can be true.

This is different from the original argument, which is saying that belief in something = reality. Frank can still be an embezzler regardless of what the prosecutor wants to do, in the same way that the oven can still be on even if Makoto doesn't believe it to be so.

Silly Makoto.


Posts: 14
Joined: Sun Mar 22, 2015 6:11 pm

Re: reasoning question

Postby tequilawine » Sun Mar 22, 2015 7:29 pm

Thank you guys.

I think the original stimulus is A to B, then not B to not C.

whereas Option A is A to B, then B to A.( condition to sufficient misuse)

For option C, the tricky things I didn't take into the "he believe" situation into account that is as the A part in the original stimulus, although I have notice it missing from the following sentence.

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