• 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
  • 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
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • 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
  • examPAL
    Most awarded test prep in the world
    Now free for 30 days

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider

Fraction Cancellation Rules

This topic has 2 expert replies and 3 member replies
stevennu Senior | Next Rank: 100 Posts Default Avatar
Joined
18 May 2013
Posted:
54 messages
Followed by:
1 members
Upvotes:
1

Fraction Cancellation Rules

Post Sun Aug 04, 2013 4:42 pm
I'm working through the Manhattan GMAT quant books and came across the following question.

Simplify: 10X / 5 + X

Why can't we simplify by cancelation? I know there are rules that regulate when we can and cannot cancel but I cannot seem to find a concise set of rules anywhere. Can someone shed some light?

Thanks

  • +1 Upvote Post
  • Quote
  • Flag
stevennu Senior | Next Rank: 100 Posts Default Avatar
Joined
18 May 2013
Posted:
54 messages
Followed by:
1 members
Upvotes:
1
Post Tue Aug 06, 2013 8:25 am
Matt@VeritasPrep wrote:
One way of thinking about it:

(10X + 8)/2 = (10X)/2 + 8/2 = 5x + 4

Since you can break the sum into two fractions, you can break them up, then reduce each one individually.

But (10X)/(8+2) is NOT (10x)/8 + (10x)/2, or (5/4)x + 5x ... it's (10X)/10, or x.

So you CAN'T break these up into two fractions and reduce each part individually.

As for fraction rules, how about:

http://isites.harvard.edu/fs/docs/icb.topic760749.files/webAPPEodd.pdf
It's clearly been a while since highschool algebra...

Thanks.

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Matt@VeritasPrep GMAT Instructor
Joined
12 Sep 2012
Posted:
2640 messages
Followed by:
113 members
Upvotes:
625
Target GMAT Score:
V51
GMAT Score:
780
Post Mon Aug 05, 2013 6:44 pm
One way of thinking about it:

(10X + 8)/2 = (10X)/2 + 8/2 = 5x + 4

Since you can break the sum into two fractions, you can break them up, then reduce each one individually.

But (10X)/(8+2) is NOT (10x)/8 + (10x)/2, or (5/4)x + 5x ... it's (10X)/10, or x.

So you CAN'T break these up into two fractions and reduce each part individually.

As for fraction rules, how about:

http://isites.harvard.edu/fs/docs/icb.topic760749.files/webAPPEodd.pdf

  • +1 Upvote Post
  • Quote
  • Flag
Enroll in a Veritas Prep GMAT class completely for FREE. Wondering if a GMAT course is right for you? Attend the first class session of an actual GMAT course, either in-person or live online, and see for yourself why so many students choose to work with Veritas Prep. Find a class now!

GMAT/MBA Expert

Post Mon Aug 05, 2013 12:08 am
Hi stevennu,

What you've typed in your post needs some clarification.

The fraction that you want to simplify...is it this:

10X/5 + X

or is it this:

10X / (5 + X)

GMAT assassins aren't born, they're made,
Rich

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag
stevennu Senior | Next Rank: 100 Posts Default Avatar
Joined
18 May 2013
Posted:
54 messages
Followed by:
1 members
Upvotes:
1
Post Mon Aug 05, 2013 11:24 am
The latter.

10X/(5+X)

  • +1 Upvote Post
  • Quote
  • Flag
stevennu Senior | Next Rank: 100 Posts Default Avatar
Joined
18 May 2013
Posted:
54 messages
Followed by:
1 members
Upvotes:
1
Post Mon Aug 05, 2013 11:53 am
I think the following link pretty much spells out the rule I was looking for.

That is, you cannot reduce part of a sum or part of a difference. Can you provide me any other links or examples?

http://www.regentsprep.org/Regents/math/ALGEBRA/AV5/reducefrac.htm

Thanks.

  • +1 Upvote Post
  • Quote
  • Flag

Best Conversation Starters

1 lheiannie07 108 topics
2 ardz24 68 topics
3 Roland2rule 65 topics
4 LUANDATO 53 topics
5 VJesus12 52 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description GMATGuruNY

The Princeton Review Teacher

146 posts
2 image description Jeff@TargetTestPrep

Target Test Prep

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

EMPOWERgmat

114 posts
4 image description Scott@TargetTestPrep

Target Test Prep

101 posts
5 image description EconomistGMATTutor

The Economist GMAT Tutor

85 posts
See More Top Beat The GMAT Experts