• Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh

DS on OG

This topic has 6 member replies
magical cook Master | Next Rank: 500 Posts Default Avatar
Joined
30 Jul 2006
Posted:
484 messages
Followed by:
1 members
Thanked:
2 times

DS on OG

Post Thu Aug 03, 2006 12:47 am
Elapsed Time: 00:00
  • Lap #[LAPCOUNT] ([LAPTIME])
    I would appreciate it if someone could explain this why.... t

    hanks in advance!!!
    Jane

    If X and Y are positive intergers such that X = 8Y + 12, what is the common divisor of X and Y?

    1) X=12u where u is an integer
    2) y=12z where z is an integer

    The answer is B and only question 2 is correct.

    Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
    gdhiman Junior | Next Rank: 30 Posts Default Avatar
    Joined
    31 Jul 2006
    Posted:
    12 messages
    Post Thu Aug 03, 2006 10:40 am
    Good one.

    putting in first data to the above equation gets us: 12u = 8y + 12 (u cannot get a common divisor from this).

    putting in second data provided we get:
    x = 8*12z + 12. So we know 12 divides X for sure, and we also know y is a multiple of 12. So 12 is the common divisor.

    Hope i made sense. let me know if u need more clarification.

    dblazquez Senior | Next Rank: 100 Posts
    Joined
    29 Apr 2006
    Posted:
    37 messages
    Thanked:
    1 times
    Post Thu Aug 03, 2006 11:03 am
    Hey, i was also trying to solve this good one Smile

    Why on the statement I we can state that you cannot get a common divisor from 12u = 8y + 12, what about 2 and four?

    gdhiman Junior | Next Rank: 30 Posts Default Avatar
    Joined
    31 Jul 2006
    Posted:
    12 messages
    Post Thu Aug 03, 2006 7:58 pm
    dblazquez wrote:
    Hey, i was also trying to solve this good one Smile

    Why on the statement I we can state that you cannot get a common divisor from 12u = 8y + 12, what about 2 and four?
    Coz what if y = 1. then 2 is not a common divisor or even 4.

    dblazquez Senior | Next Rank: 100 Posts
    Joined
    29 Apr 2006
    Posted:
    37 messages
    Thanked:
    1 times
    Post Sat Aug 05, 2006 12:59 pm
    sorry for the delay
    hmm, 12u = 8y + 12, with y = 1 is 20 therefore 2 is common divisor, thats why i was confused... i cant see the mistake

    daniel

    gdhiman Junior | Next Rank: 30 Posts Default Avatar
    Joined
    31 Jul 2006
    Posted:
    12 messages
    Post Sat Aug 05, 2006 10:50 pm
    dblazquez wrote:
    sorry for the delay
    hmm, 12u = 8y + 12, with y = 1 is 20 therefore 2 is common divisor, thats why i was confused... i cant see the mistake

    daniel
    OK.. so i will try to detail it out.:

    If X and Y are positive intergers such that X = 8Y + 12, what is the common divisor of X and Y?

    1) X=12u where u is an integer
    2) y=12z where z is an integer

    In the first option, we have 2 equations:
    X=12u & X=8Y + 12
    Lets make Y=1, we get x=20.
    So there is no common divisor of 1 and 20. (2 is not a common divisor).

    In the second option, we have 2 equations:
    Y=12z & X=96z + 12.
    Lets make z=1, We get Y=12 and X=108.
    (So now we have a common divisor for every value of z).

    dblazquez Senior | Next Rank: 100 Posts
    Joined
    29 Apr 2006
    Posted:
    37 messages
    Thanked:
    1 times
    Post Sun Aug 06, 2006 6:51 am
    Hey thanks a lot for the explanation, now i see it much clearer... i hate this number properties problem... defintely is B

    Best Conversation Starters

    1 lheiannie07 116 topics
    2 LUANDATO 62 topics
    3 swerve 62 topics
    4 ardz24 61 topics
    5 AAPL 58 topics
    See More Top Beat The GMAT Members...

    Most Active Experts

    1 image description Brent@GMATPrepNow

    GMAT Prep Now Teacher

    172 posts
    2 image description Scott@TargetTestPrep

    Target Test Prep

    154 posts
    3 image description Rich.C@EMPOWERgma...

    EMPOWERgmat

    131 posts
    4 image description EconomistGMATTutor

    The Economist GMAT Tutor

    127 posts
    5 image description GMATGuruNY

    The Princeton Review Teacher

    125 posts
    See More Top Beat The GMAT Experts