GMATprep Geometry question

discreet wrote:I think we can generalize this....the Lowest distance should be the GCD\HCF of the two numbers 5 and 7 = 35...
So,lowest possible distance is 1/35....you can test it with any no. of options to satisfy yrself and then perform the test that drholmer has given ....eg: 2 and 5 parts , 6 and 7 parts, 3 and 4 parts etc etc

Ian Stewart wrote:

gmattester wrote:

discreet wrote:I think we can generalize this....the Lowest distance should be the GCD\HCF of the two numbers 5 and 7 = 35...
So,lowest possible distance is 1/35....you can test it with any no. of options to satisfy yrself and then perform the test that drholmer has given ....eg: 2 and 5 parts , 6 and 7 parts, 3 and 4 parts etc etc

Can someone verify this method...
Or if someone has shorter method to solve this question with proper logic

It's not likely you'll see this exact type of question again, but the method is correct, although discreet surely means the LCM, not the GCD. I'll only prove it if someone asks, though; the proof is a bit abstract. On the GMAT, you would not be expected to know this kind of fact- for this question, it's easy enough to write down all of the fractions with a common denominator, 35:

5/35, 7/35, 10/35, 14/35, 15/35, 20/35, 21/35, 25/35, 28/35, 30/35

and you can see all the possible distances that way.

gmattester wrote:

Ian Stewart wrote:

gmattester wrote:

discreet wrote:I think we can generalize this....the Lowest distance should be the GCD\HCF of the two numbers 5 and 7 = 35...
So,lowest possible distance is 1/35....you can test it with any no. of options to satisfy yrself and then perform the test that drholmer has given ....eg: 2 and 5 parts , 6 and 7 parts, 3 and 4 parts etc etc

Can someone verify this method...
Or if someone has shorter method to solve this question with proper logic

It's not likely you'll see this exact type of question again, but the method is correct, although discreet surely means the LCM, not the GCD. I'll only prove it if someone asks, though; the proof is a bit abstract. On the GMAT, you would not be expected to know this kind of fact- for this question, it's easy enough to write down all of the fractions with a common denominator, 35:

5/35, 7/35, 10/35, 14/35, 15/35, 20/35, 21/35, 25/35, 28/35, 30/35

and you can see all the possible distances that way.

Thanks Ian.....
Much clear now.

mehravikas wrote:I have been preparing for GMAT and I have finished OG, Kaplan, PR. I just gave a GMAT prep yesterday, and to be honest could get only 21 questions correct in quant. I have always scored more than 80% on all the gmat practice material. But I guess Gmat prep is entierly different from Kaplan (way too tough), PR and OG (too easy).

Would you recommend more practice to these kind of questions or some other material???

gmattester wrote:

Ian Stewart wrote:

gmattester wrote:

discreet wrote:I think we can generalize this....the Lowest distance should be the GCD\HCF of the two numbers 5 and 7 = 35...
So,lowest possible distance is 1/35....you can test it with any no. of options to satisfy yrself and then perform the test that drholmer has given ....eg: 2 and 5 parts , 6 and 7 parts, 3 and 4 parts etc etc

Can someone verify this method...
Or if someone has shorter method to solve this question with proper logic

It's not likely you'll see this exact type of question again, but the method is correct, although discreet surely means the LCM, not the GCD. I'll only prove it if someone asks, though; the proof is a bit abstract. On the GMAT, you would not be expected to know this kind of fact- for this question, it's easy enough to write down all of the fractions with a common denominator, 35:

5/35, 7/35, 10/35, 14/35, 15/35, 20/35, 21/35, 25/35, 28/35, 30/35

and you can see all the possible distances that way.

Thanks Ian.....
Much clear now.

sudhir3127 wrote:

mehravikas wrote:I have been preparing for GMAT and I have finished OG, Kaplan, PR. I just gave a GMAT prep yesterday, and to be honest could get only 21 questions correct in quant. I have always scored more than 80% on all the gmat practice material. But I guess Gmat prep is entierly different from Kaplan (way too tough), PR and OG (too easy).

Would you recommend more practice to these kind of questions or some other material???

gmattester wrote:

Ian Stewart wrote:

gmattester wrote:

discreet wrote:I think we can generalize this....the Lowest distance should be the GCD\HCF of the two numbers 5 and 7 = 35...
So,lowest possible distance is 1/35....you can test it with any no. of options to satisfy yrself and then perform the test that drholmer has given ....eg: 2 and 5 parts , 6 and 7 parts, 3 and 4 parts etc etc

Can someone verify this method...
Or if someone has shorter method to solve this question with proper logic

It's not likely you'll see this exact type of question again, but the method is correct, although discreet surely means the LCM, not the GCD. I'll only prove it if someone asks, though; the proof is a bit abstract. On the GMAT, you would not be expected to know this kind of fact- for this question, it's easy enough to write down all of the fractions with a common denominator, 35:

5/35, 7/35, 10/35, 14/35, 15/35, 20/35, 21/35, 25/35, 28/35, 30/35

and you can see all the possible distances that way.

Thanks Ian.....
Much clear now.

Request you to please post ur question on an appropriate thread.. i am sure u will get the answers quickly and in more organised way...

thanks