So far this summer there has been no rain in the valley. But usually

Question

So far this summer there has been no rain in the valley. But usually a few inches of rain fall there each summer. Since only one week of summer is left, it will probably rain in the valley within the next week.

The flawed pattern of reasoning in the argument above is most similar to that in which one of the following arguments?

(A) Aisha has finished proofreading all but the last two pages of an issue of the journal Periodos and has encountered no errors. However, there are sometimes a few errors in an issue of the journal Periodos. So there may be errors in the pages that Aisha has not yet checked.

(B) There are generally few errors in an issue of the journal Periodos. Aisha has finished proofreading all but the last two pages of an issue of this journal but has encountered no errors. Hence, there are probably no errors in the pages that Aisha has not yet checked in this issue of the journal.

(C) On average, there are a few errors in an issue of the journal Periodos. Aisha has finished proofreading all but the last two pages of an issue of this journal but has encountered no errors. So there are probably errors in the pages she has not yet checked in this issue of the journal.

(D) Aisha has proofread several issues of the journal Periodos and has encountered no errors. But there are seldom any errors in an issue of this journal. So there will probably be no errors in the next issue of the journal Periodos that she proofreads.

(E) There usually are errors in each issue of the journal Periodos. Since Aisha has finished proofreading the latest issue of this journal and has detected no errors, Aisha has probably made a mistake in her proofreading.

unraveled · Answer

So far  this summer there has been  no rain in the valley . But  usually  a few inches of  rain fall there each summer . Since  only one week of summer  is left, it will  probably rain  in the valley  within the next week .

The flawed pattern of reasoning in the argument above is most similar to that in which one of the following arguments?

(A) Aisha has finished  proofreading all but the last two pages  of an issue of the journal Periodos and has  encountered no errors . However, there are  sometimes a few errors  in an issue of the journal Periodos. So there  may be errors  in the pages that Aisha has  not yet checked .

(B) There are  generally few errors in an issue  of the journal Periodos. Aisha has finished  proofreading all but the last two pages  of an issue of this journal but has  encountered no errors . Hence, there are  probably   no errors  in the pages that Aisha has  not yet checked  in this issue of the journal.

(C)  On average, there are a few errors  in an issue of the journal Periodos. Aisha has finished  proofreading all but the last two pages  of an issue of this journal but has  encountered no errors . So there are  probably errors  in the pages she has  not yet checked  in this issue of the journal. - CORRECT.

(D) Aisha has  proofread   several issues  of the journal Periodos and has  encountered no errors . But there are  seldom any errors  in  an issue of this journal . So there will  probably be no errors  in the  next issue  of the journal Periodos that she proofreads.

(E) There  usually are errors  in  each issue of the journal  Periodos. Since Aisha has finished  proofreading  the  latest issue  of this journal and has  detected no errors , Aisha has  probably   made a mistake  in her proofreading.

Only B and C were left for me. B had slight change of conclusion.

Answer C.

sravojitgoswami · Answer

KarishmaB  would you please explain why the Answer is option C and not option A?

SCirone23 · Answer

sravojitgoswami

Option A says sometimes vs. Option C says on average.

On average leads towards an error likely being in the remaining pages (Option C), which is similar to the passages wording of ‘usually’.

KarishmaB · Answer

sravojitgoswami

The flaw is this: Average is applied to each case.

Usually there is a bit of rain. No rain yet so it will probably happen in the next 2 weeks. That is, this summer will also adhere to the averages.

(A) Aisha has finished proofreading all but the last two pages of an issue of the journal Periodos and has encountered no errors. However, there are sometimes a few errors in an issue of the journal Periodos. So there may be errors in the pages that Aisha has not yet checked.

Sometimes (not usually) there are errors. No error yet so likely errors in the last 2 pages. 
This error is different. It says what is true sometimes is likely to be true in this case too. This is not the same as our original error.

(C) On average, there are a few errors in an issue of the journal Periodos. Aisha has finished proofreading all but the last two pages of an issue of this journal but has encountered no errors. So there are probably errors in the pages she has not yet checked in this issue of the journal.

On average there are a few errors. No errors yet so likely errors in last two pages. 
Same as our original error.

Answer (C)

PiyushParwani · Answer

I don't know whether this thing has to do with averages. I got the question wrong, but now that I have understood it fully, I would try to explain.

When it comes to the argument, it says that 'It usually rains in the summer' -> There has been no rain this summer -> (Conclusion) It will 'probably' rain in the last 1 week.

When it comes to Argument C, it follows the same flaw that if something that is supposed to happen has not happened in the already passed time, it probably will happen in the remaining time, i.e. in the end.

When it comes to, 'It usually(average) has errors -> Checked all but the last two with no errors -> Last two 'probably' will have errors.

So far this summer there has been no rain in the valley. But usually

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

So far this summer there has been no rain in the valley. But usually

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards