rainfall problem

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kiennguyen
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Thu Nov 05, 2009 8:19 pm

imo D. OA pls

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Testluv
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Thu Nov 05, 2009 8:47 pm

kiennguyen wrote: imo D. OA pls Hi kiennguyen, Actually, choice D is mathematically impossible. This is because the range for moderate rain is something just over 1 inch up to 2 inches. To test it, let's maximize rain per moderately rain in 1990 at 2 inches, and minimize rain per moderately rainy day in 1910 at 1.00000.....1 inch. So if you had an equal number of moderately rainy days in both years, then the ratio of 1990 mod rain/1910 mod rain would be: 2/1.0000.....1. This already makes it mathematically impossible. But of course, there were fewer moderately rainy days in 1990, which means there were more in 1910, so our ratio would really look like: 2/(1.00000...1+). Which means it is mathematically impossible for the amount of rain that fell on moderately rainy days in 1990 to have been more than twice as great as the amount of rain that fell on moderately rainy days in 1910. _________________ Kaplan Teacher in Toronto Last edited by Testluv on Fri Nov 06, 2009 12:47 am; edited 1 time in total

kiennguyen
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Fri Nov 06, 2009 12:26 am

Testluv wrote: kiennguyen wrote: imo D. OA pls Hi kiennguyen, Actually, choice D is mathematically impossible. This is because the range for moderate rain is something just over 1 cm up to 2 cm. To test it, let's maximize rain per moderately rain in 1990 at 2 inches, and minimize rain per moderately rainy day in 1910 at 1.00000.....1 inch. So if you had an equal number of moderately rainy days in both years, then the ratio of 1990 mod rain/1910 mod rain would be: 2/1.0000.....1. This already makes it mathematically impossible. But of course, there were fewer moderately rainy days in 1990, which means there were more in 1910, so our ratio would really look like: 2/(1.00000...1+). Which means it is mathematically impossible for the amount of rain that fell on moderately rainy days in 1990 to have been more than twice as great as the amount of rain that fell on moderately rainy days in 1910. thanks, Testluv! i didn't see your post before i gave my idea! your explanation is perfect. i hope you can help me out in the future!

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Thu Nov 12, 2009 1:15 pm

IMO - D

gettingready
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Fri Nov 13, 2009 3:18 pm

Hello crackgmat007, Thank you for your very detailed explanation. I was going for D. Although, I perfectly understood your explanation of why D is not correct, to me choice A still does not make sense.Could you possible deepen the explanation of why A is correct? Or is it more of " the best choice" out of the worst? Thanks

palvarez
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Fri Nov 13, 2009 4:35 pm

gettingready wrote: Hello crackgmat007, Thank you for your very detailed explanation. I was going for D. Although, I perfectly understood your explanation of why D is not correct, to me choice A still does not make sense.Could you possible deepen the explanation of why A is correct? Or is it more of " the best choice" out of the worst? Thanks I know why it doesn't take sense for (A) to be correct. But notice the modal quantifier "possibly". Possibly true is not same as necessarily true. (A) is not necessarily true, but possibly true. When it comes to D, it is not possibly true, which means "necessarily" false. Not (possibly true) = (not possibly) (not true) = necessarily false.

heshamelaziry
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Fri Nov 13, 2009 5:32 pm

[quote="Testluv"] kiennguyen wrote: imo D. OA pls Hi kiennguyen, Actually, choice D is mathematically impossible. This is because the range for moderate rain is something just over 1 inch up to 2 inches. To test it, let's maximize rain per moderately rain in 1990 at 2 inches, and minimize rain per moderately rainy day in 1910 at 1.00000.....1 inch. So if you had an equal number of moderately rainy days in both years, then the ratio of 1990 mod rain/1910 mod rain would be: 2/1.0000.....1. This already makes it mathematically impossible. But of course, there were fewer moderately rainy days in 1990, which means there were more in 1910, so our ratio would really look like: 2/(1.00000...1+). Which means it is mathematically impossible for the amount of rain that fell on moderately rainy days in 1990 to have been more than twice as great as the amount of rain that fell on moderately rainy days in 1910.[/quot Testluv, is this a LSAT type question ? Thanks,

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Testluv
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Fri Nov 13, 2009 6:11 pm

Quote: Testluv, is this a LSAT type question ? Nope. This is a high-level GMAT kind of question. LSAT won't test quant this furiously. _________________ Kaplan Teacher in Toronto