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

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas 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
  • 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
  • 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
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

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

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • 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

What is w + z? - Number Properties

This topic has 3 expert replies and 1 member reply
LulaBrazilia Master | Next Rank: 500 Posts Default Avatar
Joined
31 Mar 2009
Posted:
116 messages
Followed by:
1 members

What is w + z? - Number Properties

Post Tue Feb 25, 2014 8:43 am
If the product of the integers w, x, y, and z is 770 and if 1 < w < x < y < z, what is the value of w + z ?

A) 10

B) 13

C) 16

D) 18

E) 21

  • +1 Upvote Post
  • Quote
  • Flag
Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!

GMAT/MBA Expert

Post Tue Feb 25, 2014 2:29 pm
Hi LulaBrazilia,

Each of the explanations in this string focused on "prime factorization", which is a MUST to solving this question.

The reason you KNOW that prime factorization is necessary is in the wording and "design" of the question. Here's why:

The question asks for THE sum of the biggest and smallest variables, NOT what COULD BE the sum. Since 1
For example, the numbers 2, 6, 8 and 10 would have a product of 960. So do the numbers 2, 3, 8 and 20. In this scenario z could be different values, which would change the answer to the question. But this scenario does not match the wording of the prompt.

When thinking about how to solve a problem, pay attention to the specific wording of the prompt. GMAT questions are very carefully worded and often provide clues as to how to approach the problem (and sometimes the easiest approach to it).

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

_________________
Contact Rich at Rich.C@empowergmat.com

  • +1 Upvote Post
  • Quote
  • Flag
theCodeToGMAT Legendary Member
Joined
14 Aug 2012
Posted:
1556 messages
Followed by:
34 members
Upvotes:
448
Target GMAT Score:
750
GMAT Score:
650
Post Tue Feb 25, 2014 9:49 am
wxyz = 770

770 = 7 x 11 x 5 x 2

Since, 1 < w < x < y < z

w = 2
z = 11

w + z = 13

{B}

_________________
R A H U L

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Patrick_GMATFix GMAT Instructor
Joined
21 May 2010
Posted:
1053 messages
Followed by:
98 members
Upvotes:
335
Post Tue Feb 25, 2014 8:54 am
Questions about factors & multiples are usually best handled by breaking numbers into their prime factors, since these primes are the building blocks of all integers. The full solution below is taken from the GMATFix App.

ttp://www.youtube.com/watch?v=PBsC7k70R90" target="_blank">

-Patrick

_________________


    Ask me about tutoring.

  • +1 Upvote Post
  • Quote
  • Flag

GMAT/MBA Expert

Post Tue Feb 25, 2014 8:46 am
LulaBrazilia wrote:
If the product of the integers w, x, y, and z is 770 and if 1 < w < x < y < z, what is the value of w + z ?

A) 10
B) 13
C) 16
D) 18
E) 21
This requires us to use prime factorization.
770 = (2)(5)(7)(11)

So, if 1 < w < x < y < z then:
w = 2
x = 5
y = 7
z = 11

This means that w + z = 2 + 11 = 13 = B

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with Beat The GMAT's free 60-Day Study Guide

Check out the online reviews of our course
Come see all of our free resources

  • +1 Upvote Post
  • Quote
  • Flag
GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!

Best Conversation Starters

1 Roland2rule 161 topics
2 lheiannie07 110 topics
3 ardz24 56 topics
4 LUANDATO 53 topics
5 Vincen 50 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

151 posts
2 image description Jeff@TargetTestPrep

Target Test Prep

145 posts
3 image description GMATGuruNY

The Princeton Review Teacher

114 posts
4 image description Rich.C@EMPOWERgma...

EMPOWERgmat

111 posts
5 image description Scott@TargetTestPrep

Target Test Prep

98 posts
See More Top Beat The GMAT Experts