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A one meter long wire is to be marked for cutting at intervals of fift [#permalink]
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 11 Jan 2018, 23:14
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64% (01:26) correct 36% (01:23) wrong based on 104 sessions
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Re: A one meter long wire is to be marked for cutting at intervals of fift [#permalink]
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21 Jan 2018, 23:53
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Bunuel wrote: A one meter long wire is to be marked for cutting at intervals of fifths and thirds. How long, in meters, is the largest segment of the wire if the wire is cut at the marked intervals?
A. 1/15
B. 2/15
C. 1/5
D. 4/15
E. 9/15 So when we mark at intervals of thirds, the marks are at the positions 1/3 and 2/3 from the starting point. And when we mark at intervals of fifths, the marks are at the positions 1/5, 2/5, 3/5, 4/5 from the starting point. To make the comparison easier, we can write 1/3 and 2/3 as 5/15 and 10/15 respectively. Similarly, we can write 1/5, 2/5, 3/5, 4/5 as 3/15, 6/15, 9/15 and 12/15 respectively. So, now if we look at all the above 6 marks one by one from the starting point, the marks are at the following positions: 3/15 from start, 5/15 from start, 6/15, 9/15, 10/15 and 12/15 respectively. Cutting at exactly these 6 marks, we will get 7 pieces of wire which will be of following lengths (from the start): 3/15, 2/15, 1/15, 3/15, 1/15, 2/15 and 3/15 respectively. The largest length as we can see is that of 3/15 or 1/5. Hence C answer
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Re: A one meter long wire is to be marked for cutting at intervals of fift [#permalink]
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22 Jan 2018, 00:29
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C Lets say the wire length is 1000mm (1m). it is cut at every 1/5th i.e 200m, 400mm, 600mm, 800mm and again at every 1/3rd i.e 333.33mm and 666.66mm. Clearly the longest distance of the cut wire is 0 to 200mm and 800mm to 1000mm. which is 200/1000 = 1/5. Hence C
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Re: A one meter long wire is to be marked for cutting at intervals of fift [#permalink]
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23 Jan 2018, 08:57
Bunuel wrote: A one meter long wire is to be marked for cutting at intervals of fifths and thirds. How long, in meters, is the largest segment of the wire if the wire is cut at the marked intervals?
A. 1/15
B. 2/15
C. 1/5
D. 4/15
E. 9/15 So our 5ths are marked at 1/5, 2/5, 3/5 and 4/5. Our 3rds are marked at 1/3 and 2/3. If we use a common denominator of 15 our 5ths are marked at: 3/15, 6/15, 9/15, 12/15 And our 3rds at: 5/15, 10/15 So the largest segment 3/15 = 1/5 (occurred between the 1/5 mark and one end of the wire,between the 4/5 mark and the other end of the wire, or between the 2/5 mark and 3/5 mark). Answer: C
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Re: A one meter long wire is to be marked for cutting at intervals of fift [#permalink]
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24 Jan 2018, 21:03
amanvermagmat wrote: Bunuel wrote: A one meter long wire is to be marked for cutting at intervals of fifths and thirds. How long, in meters, is the largest segment of the wire if the wire is cut at the marked intervals?
A. 1/15
B. 2/15
C. 1/5
D. 4/15
E. 9/15 So when we mark at intervals of thirds, the marks are at the positions 1/3 and 2/3 from the starting point. And when we mark at intervals of fifths, the marks are at the positions 1/5, 2/5, 3/5, 4/5 from the starting point. To make the comparison easier, we can write 1/3 and 2/3 as 5/15 and 10/15 respectively. Similarly, we can write 1/5, 2/5, 3/5, 4/5 as 3/15, 6/15, 9/15 and 12/15 respectively. So, now if we look at all the above 6 marks one by one from the starting point, the marks are at the following positions: 3/15 from start, 5/15 from start, 6/15, 9/15, 10/15 and 12/15 respectively. Cutting at exactly these 6 marks, we will get 7 pieces of wire which will be of following lengths (from the start): 3/15, 2/15, 1/15, 3/15, 1/15, 2/15 and 3/15 respectively. The largest length as we can see is that of 3/15 or 1/5. Hence C answerI was not able to solve this.. Bunuel's soln seems most elegant and easy to understand for me! What i still can't wrap my head around is that why this question seems so hard!! is it just me? 
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Re: A one meter long wire is to be marked for cutting at intervals of fift [#permalink]
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24 Jan 2018, 22:49
krish76 wrote: amanvermagmat wrote: Bunuel wrote: A one meter long wire is to be marked for cutting at intervals of fifths and thirds. How long, in meters, is the largest segment of the wire if the wire is cut at the marked intervals?
A. 1/15
B. 2/15
C. 1/5
D. 4/15
E. 9/15 So when we mark at intervals of thirds, the marks are at the positions 1/3 and 2/3 from the starting point. And when we mark at intervals of fifths, the marks are at the positions 1/5, 2/5, 3/5, 4/5 from the starting point. To make the comparison easier, we can write 1/3 and 2/3 as 5/15 and 10/15 respectively. Similarly, we can write 1/5, 2/5, 3/5, 4/5 as 3/15, 6/15, 9/15 and 12/15 respectively. So, now if we look at all the above 6 marks one by one from the starting point, the marks are at the following positions: 3/15 from start, 5/15 from start, 6/15, 9/15, 10/15 and 12/15 respectively. Cutting at exactly these 6 marks, we will get 7 pieces of wire which will be of following lengths (from the start): 3/15, 2/15, 1/15, 3/15, 1/15, 2/15 and 3/15 respectively. The largest length as we can see is that of 3/15 or 1/5. Hence C answerI was not able to solve this.. Bunuel's soln seems most elegant and easy to understand for me! What i still can't wrap my head around is that why this question seems so hard!! is it just me? Hi Krish Have you looked at this solution: https://gmatclub.com/forum/a-one-meter- ... l#p2001263 The above solution makes it easy I guess.
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Re: A one meter long wire is to be marked for cutting at intervals of fift [#permalink]
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25 Jan 2018, 17:38
I was not able to solve this.. Bunuel's soln seems most elegant and easy to understand for me! What i still can't wrap my head around is that why this question seems so hard!! is it just me? [/quote] Hi Krish Have you looked at this solution: https://gmatclub.com/forum/a-one-meter- ... l#p2001263 The above solution makes it easy I guess.[/quote] Yes, it does. thank you. quants solution always looks super easy.. i just couldn't visualize the question  and was taken aback by the wording.
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Re: A one meter long wire is to be marked for cutting at intervals of fift
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25 Jan 2018, 17:38
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