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The perimeter of a rectangular garden is 360 ft. What is the [#permalink]
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06 Aug 2007, 18:46
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This topic is locked. If you want to discuss this question please repost it in the respective forum. This isn't a tough problem, but I have a question about it: The perimeter of a rectangular garden is 360 ft. What is the length of the garden? I the length is twice the width II the difference between the length and width is 60 ft ___________________________________________________________ so i was able to quickly use 1 to get l= 120ft. no problem. I picked A because I thought statement two just says that l and w have 60ft between them. l could be 60 and w 120 and vice versa. since the distance between two numbers is always positive, the difference is ab or ba it doesn't matter (what's the difference between 5 and 3 53 = 35) lw=60 means l=w+60 or w=l+60. insufficient! I even looked this up on the internet to prove i am not crazy: http://mathforum.org/library/drmath/view/63137.html



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Since we're told the garden is rectangular, then if the length is denoted by l and the width by w, we have 2(w+l) = 360, w+l = 180
St1:
l = 2w. Then we have w+l = 180 > l/2 + l = 180. Can solve for l. Sufficient.
St2:
lw = 60, then w = l60. Substitute this to w+l = 180 to solve for l. Sufficient.
ans D



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ywilfred wrote: Since we're told the garden is rectangular, then if the length is denoted by l and the width by w, we have 2(w+l) = 360, w+l = 180
St1: l = 2w. Then we have w+l = 180 > l/2 + l = 180. Can solve for l. Sufficient.
St2: lw = 60, then w = l60. Substitute this to w+l = 180 to solve for l. Sufficient.
ans D
ywilfred,
my problem is that mathematically speaking the statement "the difference between l and w" = lw =60. which is not sufficient. I even looked it up on a college's website to make sure I wasn't crazy.



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anonymousegmat wrote: ywilfred wrote: Since we're told the garden is rectangular, then if the length is denoted by l and the width by w, we have 2(w+l) = 360, w+l = 180
St1: l = 2w. Then we have w+l = 180 > l/2 + l = 180. Can solve for l. Sufficient.
St2: lw = 60, then w = l60. Substitute this to w+l = 180 to solve for l. Sufficient.
ans D ywilfred, my problem is that mathematically speaking the statement "the difference between l and w" = lw =60. which is not sufficient. I even looked it up on a college's website to make sure I wasn't crazy.
I see your point. I think if the question says "difference between x and y", you can conclude that xy. If it says like "distance between x and y", then it is another story. Just my thought.



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Re: OG Green DS [#permalink]
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06 Aug 2007, 19:19
Shouldn't one assume that length > width?



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bkk145 wrote: anonymousegmat wrote: ywilfred wrote: Since we're told the garden is rectangular, then if the length is denoted by l and the width by w, we have 2(w+l) = 360, w+l = 180
St1: l = 2w. Then we have w+l = 180 > l/2 + l = 180. Can solve for l. Sufficient.
St2: lw = 60, then w = l60. Substitute this to w+l = 180 to solve for l. Sufficient.
ans D ywilfred, my problem is that mathematically speaking the statement "the difference between l and w" = lw =60. which is not sufficient. I even looked it up on a college's website to make sure I wasn't crazy. I see your point. I think if the question says "difference between x and y", you can conclude that xy. If it says like "distance between x and y", then it is another story. Just my thought.
well, the difference between any x and any y, IS the distance between X and Y on a number line. and distance is always positive, hence the absolute value. but i have made a mental note, for sure. I just think that this is the GMAT playing hard and fast with math IMHO. if this would have been a PS instead of DS, I would have never even blinked.
grrr. 9 more days to go.



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Re: OG Green DS [#permalink]
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06 Aug 2007, 19:25
Andr359 wrote: Shouldn't one assume that length > width?
no. you should never assume that, ever.
even if you did, the designation of what is "l" and "w" is arbitrary. just turn the rectangular solid around, or on a different side and l is now w, h could be l.



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I agree with Andr359. Not sure about this, but I think by definition the length of a rectangle is the LONG side. Never heard of one with a length of 10 and width of 20.



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Robin in NC wrote: I agree with Andr359. Not sure about this, but I think by definition the length of a rectangle is the LONG side. Never heard of one with a length of 10 and width of 20.
dude, if that's the case then the OG problem makes perfect sense and I can stop trying to find GMAC's complaint phone #. i can't believe i never learned that. i took the freaking Veritas course! LOL! as i type this i am looking over EVERY page of the geometry book.
not anywhere do they mention this. this small little fact could have really screwed me up on the GMAT. this was a medium level question... if I got this wrong in the beginning I could have been doomed!
( Veritas sucks btw)
grrrr.



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Robin in NC wrote: I agree with Andr359. Not sure about this, but I think by definition the length of a rectangle is the LONG side. Never heard of one with a length of 10 and width of 20.
it looks like this isn't mentioned in MGMAT's geometry book either (if it is i couldn't find it but i am getting tired...)
every rectangle they have, has length labeled as the longest side, but they never specifically mention it as a rule... i learned to never take anything for granted and assume anything (especially on the gmat math section!!) so i am pretty embarrased and pissed off. this little retarded fact is pretty important, and it should have been mentioned in the $1500 prep course i took or the $26 geometry workbook i bought.
but you are 100% right. I googled it. l is longest side.
thanks guys and gals. i am glad i logged on to gmatclub tonight



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After this discussion I got curious about the actual definitions. Seems there is some room for confusion, although the American Heritage Dictionary defines length as "The measurement of the extent of something along its greatest dimension". For an interesting discussion of the mathematical definition, check out: http://mathforum.org/library/drmath/view/57801.html



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Robin in NC wrote: After this discussion I got curious about the actual definitions. Seems there is some room for confusion, although the American Heritage Dictionary defines length as "The measurement of the extent of something along its greatest dimension". For an interesting discussion of the mathematical definition, check out: http://mathforum.org/library/drmath/view/57801.html
this is pretty cool. did you know that .99999... = 1
http://polymathematics.typepad.com/poly ... y_it_.html



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It doesn't matter how your rectangle looks like. The longer side is always l.



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the .9999.... thing makes sense  if 1/3 is .3333..... why shouldn't three times that be .9999999.....



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I just wasted 30 minutes
Grr...



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so L will always be the longest side when dealing with the GMAT? I'm kind of surprised that isn't mentioned somewhere since it has such a big impact on questions like this one.



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Re: OG Green DS [#permalink]
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07 Aug 2007, 09:07
anonymousegmat wrote: This isn't a tough problem, but I have a question about it: The perimeter of a rectangular garden is 360 ft. What is the length of the garden? I the length is twice the width II the difference between the length and width is 60 ft ___________________________________________________________ so i was able to quickly use 1 to get l= 120ft. no problem. I picked A because I thought statement two just says that l and w have 60ft between them. l could be 60 and w 120 and vice versa. since the distance between two numbers is always positive, the difference is ab or ba it doesn't matter (what's the difference between 5 and 3 53 = 35) lw=60 means l=w+60 or w=l+60. insufficient! I even looked this up on the internet to prove i am not crazy: http://mathforum.org/library/drmath/view/63137.html
generally we consider the longeer side length and shorter one width.
so no matter which one is longer, it is length.



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eschn3am wrote: so L will always be the longest side when dealing with the GMAT? I'm kind of surprised that isn't mentioned somewhere since it has such a big impact on questions like this one.
yeah, that is the long and the short of it.
lol.
this really pissed me off last night, as it is a small but important fact



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Re: OG Green DS [#permalink]
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12 Aug 2009, 18:53
bumping this thread even though it is 2 years old... Today I was working on the same question from the OG Quant review and ended up wasting lots of time pondering how one can assume that the difference between l and w is l  w. It is so by definition! I feel so stupid...










