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Re: rainfall [#permalink]
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16 May 2009, 04:52
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Use POE, answer D Fact: 1990's light rainfall days <1910 light rainfall days 1990's moderate rainfall <1910's moderate rainfall total 1990's total rainfall >1910's total rainfall
Assumption: 1990's heavy rainfall >1910's heavy rainfall
In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall. In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910.
If the statements above are true, then it is also possible that in Patton City
A. the number of days with heavy rainfall was lower in 1990 than in 1910 >counter assumption B. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910 >counter fact C. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910 >counter fact D. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910 >best E. the average amount of rainfall per month was lower in 1990 than in 1910 >total of 1990> total of 1910 > average 1990 > average 1910 >can't be true



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Re: rainfall [#permalink]
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16 May 2009, 05:32
Agree with D.



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Re: rainfall [#permalink]
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16 May 2009, 14:20
gmatee wrote: In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall. In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910.
If the statements above are true, then it is also possible that in Patton City
A. the number of days with heavy rainfall was lower in 1990 than in 1910 B. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910 C. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910 D. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910 E. the average amount of rainfall per month was lower in 1990 than in 1910 A, B, & C all contradicts given info. E is impossible, if 1990's total is higher, the average is inevitably higher. This leaves us with (D), while the total number of days w/ moderate rain decreased by some small amount, but the amount of moderate rain fall increased significantly, thus increasing total rain fall.



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Re: rainfall [#permalink]
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16 May 2009, 14:22
Hmm... now that I've seen the other responses & the OA, I'm kind of puzzled. Is there an official explanation?



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Re: rainfall [#permalink]
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16 May 2009, 14:28
gmatee wrote: i picked D too, but OA is A Actually, now that I think of it. I guess it kind of makes sense from a mathematical perspective. Let x = amount of moderate rain fall. We know that on days with moderate rain, we know the amount is 1<x<2 inches. So therefore, unless "x" became more than 2, it is impossible for x to "double" from 1910 to 1990 and still be categorized as "moderate" (remember, rain greater than 2 is categorized as heavy). So I guess (A) is the only option that is possible; you could have a slight decrease in the total number of days with light/mod rain/heavy rain, but still a significant increase in the amount of light/mod/heavy rain fall (although NOT double). For example, in 1910 there were 100 days w/ moderate rain; in 1990, there were only 99 such days. However, on moderate rain days in 1910 it usually rained 1.05 inches, in 1990 this increased to 1.999 inches  NOT double but still significant. The same could apply for light/heavy rain days as well. Under such scenarios, total rainfall would still increase.



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Re: rainfall [#permalink]
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17 May 2009, 01:47
Minheequang wrote: Use POE, answer D Fact: 1990's light rainfall days <1910 light rainfall days 1990's moderate rainfall <1910's moderate rainfall total 1990's total rainfall >1910's total rainfall
Assumption: 1990's heavy rainfall >1910's heavy rainfall Dont know why you find out the assumption, a conclusion in this case, but you choose D? The question says only "possible", so A can be a candidate?
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Re: rainfall [#permalink]
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17 May 2009, 03:39
gmatee wrote: In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall. In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910.
If the statements above are true, then it is also possible that in Patton City
A. the number of days with heavy rainfall was lower in 1990 than in 1910 B. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910 C. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910 D. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910 E. the average amount of rainfall per month was lower in 1990 than in 1910 Man, after rechecking this, I found out that this is such a top tricky question We fell into the trap of illusion as if 1990's number of days with heavy rainfalls were lower than 1910's, 1990's heavy rainfall (total inches) <1910's, thus rapidly neglecting (A). However, because heavy rainfalls is >2 inches, so there's also possibility that 1990's heavy rains days<1910's, but 1990's heavy rainfalls>1910's for exp: [b]5 heavy rainfalls days in 1990 (each day 10 inches) have total inches of heavy rainfall greater than that of 10 heavy rainfall days in 1910 (each day 3 inches) ~ 50>30 looking back at the other choices: (B): counterfact (C): counterfact (D): a simplest exp: 1990 has 1 day of moderate rainfall (1,9 inches) while 1910 has 2 days of moderate rainfall (1,1 inches each) > 1,9 <2,2 > this possibility is impossible in the simplest case, hence so is it in other more complex cases >wrong (E): wrong So, A is best. POE is always a risk way of choosing incorrect choice, on the expense of risk of time



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Re: rainfall [#permalink]
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07 Jan 2011, 07:58
Minheequang wrote: gmatee wrote: In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall. In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910.
If the statements above are true, then it is also possible that in Patton City
A. the number of days with heavy rainfall was lower in 1990 than in 1910 B. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910 C. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910 D. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910 E. the average amount of rainfall per month was lower in 1990 than in 1910 Man, after rechecking this, I found out that this is such a top tricky question We fell into the trap of illusion as if 1990's number of days with heavy rainfalls were lower than 1910's, 1990's heavy rainfall (total inches) <1910's, thus rapidly neglecting (A). However, because heavy rainfalls is >2 inches, so there's also possibility that 1990's heavy rains days<1910's, but 1990's heavy rainfalls>1910's for exp: [b]5 heavy rainfalls days in 1990 (each day 10 inches) have total inches of heavy rainfall greater than that of 10 heavy rainfall days in 1910 (each day 3 inches) ~ 50>30 looking back at the other choices: (B): counterfact (C): counterfact (D): a simplest exp: 1990 has 1 day of moderate rainfall (1,9 inches) while 1910 has 2 days of moderate rainfall (1,1 inches each) > 1,9 <2,2 > this possibility is impossible in the simplest case, hence so is it in other more complex cases >wrong (E): wrong So, A is best. POE is always a risk way of choosing incorrect choice, on the expense of risk of time Why cannot E be possible? Thanks.
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Re: rainfall [#permalink]
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07 Jan 2011, 07:59
noboru wrote: Minheequang wrote: gmatee wrote: In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall. In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910.
If the statements above are true, then it is also possible that in Patton City
A. the number of days with heavy rainfall was lower in 1990 than in 1910 B. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910 C. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910 D. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910 E. the average amount of rainfall per month was lower in 1990 than in 1910 Man, after rechecking this, I found out that this is such a top tricky question We fell into the trap of illusion as if 1990's number of days with heavy rainfalls were lower than 1910's, 1990's heavy rainfall (total inches) <1910's, thus rapidly neglecting (A). However, because heavy rainfalls is >2 inches, so there's also possibility that 1990's heavy rains days<1910's, but 1990's heavy rainfalls>1910's for exp: [b]5 heavy rainfalls days in 1990 (each day 10 inches) have total inches of heavy rainfall greater than that of 10 heavy rainfall days in 1910 (each day 3 inches) ~ 50>30 looking back at the other choices: (B): counterfact (C): counterfact (D): a simplest exp: 1990 has 1 day of moderate rainfall (1,9 inches) while 1910 has 2 days of moderate rainfall (1,1 inches each) > 1,9 <2,2 > this possibility is impossible in the simplest case, hence so is it in other more complex cases >wrong (E): wrong So, A is best. POE is always a risk way of choosing incorrect choice, on the expense of risk of time Why cannot E be possible? Thanks. OK, stupid question. Obviously: (Amount Rainfall 1900)/12>(Amount Rainfall 1910)/12
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Re: rainfall [#permalink]
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11 Jan 2011, 01:09
D











