It is currently 18 Feb 2018, 20:07

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

The positive difference between Sam and Lucy’s ages is a, and the sum

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43792
The positive difference between Sam and Lucy’s ages is a, and the sum [#permalink]

Show Tags

New post 13 Dec 2015, 03:39
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

69% (00:44) correct 31% (01:03) wrong based on 39 sessions

HideShow timer Statistics

The positive difference between Sam and Lucy’s ages is a, and the sum of their ages is z. If Lucy is older than Sam, then which of the following represents Lucy’s age?

A. (z - a)/2
B. a - z/2
C. 2a + z
D. (z + a)/2
E. (a - z)/2
[Reveal] Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2015
Posts: 387
Concentration: Strategy, General Management
Re: The positive difference between Sam and Lucy’s ages is a, and the sum [#permalink]

Show Tags

New post 13 Dec 2015, 12:17
let Lucy's age be L and sam's age be S
as given,
L-S=a -- 1
L+S=z --2

adding both the equations 2L=a+z
L= (a+z)/2
Expert Post
EMPOWERgmat Instructor
User avatar
D
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 11025
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Re: The positive difference between Sam and Lucy’s ages is a, and the sum [#permalink]

Show Tags

New post 15 Dec 2015, 16:36
Hi All,

This question can be solved by TESTing VALUES.

We're given three facts about the ages of two people:
1) The positive difference between Sam and Lucy’s ages is a,
2) The sum of their ages is z.
3) Lucy is older than Sam

We're asked which of the following represents Lucy’s age:

IF....
Lucy = 3
Sam = 2
a = 3-2 = 1
z = 3+2 = 5

So we're looking for an answer that equals 3 when a=1 and z=5.

Answer A) (z - a)/2 = (5-1)/2 = 2 NOT a match
Answer B) a - z/2 = 1 - 5/2 = Negative
Answer C) 2a + z = 2+5 = 7 NOT a match
Answer D) (z + a)/2 = (6)/2 = 3 This IS a MATCH
Answer E) (a - z)/2 = (1-5)/2 = Negative

Final Answer:
[Reveal] Spoiler:
D


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

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save $75 + GMAT Club Tests Free
  Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************

Intern
Intern
avatar
Joined: 27 Oct 2015
Posts: 26
Re: The positive difference between Sam and Lucy’s ages is a, and the sum [#permalink]

Show Tags

New post 15 Dec 2015, 21:53
L > S
L - S = a
L + S = z

Adding the 2 equations
2L = a + z
Hence D
Expert Post
Target Test Prep Representative
User avatar
G
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2179
Location: United States (CA)
Re: The positive difference between Sam and Lucy’s ages is a, and the sum [#permalink]

Show Tags

New post 16 Jan 2018, 16:50
Bunuel wrote:
The positive difference between Sam and Lucy’s ages is a, and the sum of their ages is z. If Lucy is older than Sam, then which of the following represents Lucy’s age?

A. (z - a)/2
B. a - z/2
C. 2a + z
D. (z + a)/2
E. (a - z)/2


We can let Sam’s current age = S and Lucy’s current age = L; thus:

L - S = a

and

L + S = z

Adding the two equations together, we have:

2L = a + z

L = (a + z)/2

Answer: D
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Re: The positive difference between Sam and Lucy’s ages is a, and the sum   [#permalink] 16 Jan 2018, 16:50
Display posts from previous: Sort by

The positive difference between Sam and Lucy’s ages is a, and the sum

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.