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OG 12 : Problem Solving Q 225

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OG 12 : Problem Solving Q 225

by nishant raina » Wed Jan 11, 2012 10:16 am
Need help on Q 225 Problem Solving from OG 12.
I was able to follow the stem and estimate that there will be 5 cuts on pipe. But even after reading the ans explanation, still not sure about how the fractions are made.

Please help to explain how it will be solved.

Thanks
Nishant
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by pemdas » Wed Jan 11, 2012 10:32 am
there are 4 1/4 ths and 3 1/3 thrds, continue finding differences between the splits (start with the smallest)

1/4, 1/3, (1/4+1/4=1/2), (1/3+1/3=2/3), (1/4+1/4+1/4=3/4), (1/3+1/3+1/3=1)

|1/4-1/3|= difference is 1/12
|1/3-1/2|= 1/6
|1/2-2/3|= 1/6
|2/3-3/4|= 1/12
|3/4-1|= 1/4

So, 1/4; 1/6; 1/12
nishant raina wrote:Need help on Q 225 Problem Solving from OG 12.
I was able to follow the stem and estimate that there will be 5 cuts on pipe. But even after reading the ans explanation, still not sure about how the fractions are made.

Please help to explain how it will be solved.

Thanks
Nishant
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by shayam » Wed Jan 11, 2012 11:09 am
Hi Nishant,
The question is looking for different lengths of the pipe.
Hence we can take any convenient number as the size for solving instead of choosing 1 yard and working with fractions.
I go with 12 (LCM of 3 and 4) which once again simplifies my solving .

So the marking for 3rd are the 0,4,8 and 12 cut.
Marking for 4th are 0,3,6,9,12
Altogether 0,3,4,6,8,9,12
So.. different markings are (0,3) -3 positions ; (3,4) - 1 position (4,6) -2 position while rest of markings are repetitions.

With this, I can easily find out the fractions to be 3/12 , 1/12 and 2/12
which is nothing but - 1/4,1/12,1/6.
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by ArunangsuSahu » Thu Jan 12, 2012 7:12 am
Step 1: Divide the number line in 1/4ths
Step 2: Divide the number line in 1/3rds

Take each difference between 1.4th and 1/3rd interval number points
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