GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 24 Jan 2020, 22:34 ### 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

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

Author Message
TAGS:

### Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 60647
The positive difference between Sam and Lucy’s ages is a, and the sum  [#permalink]

### Show Tags 00:00

Difficulty:   35% (medium)

Question Stats: 68% (01:09) correct 33% (01:15) wrong based on 54 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

_________________
Director  G
Joined: 20 Feb 2015
Posts: 727
Concentration: Strategy, General Management
Re: The positive difference between Sam and Lucy’s ages is a, and the sum  [#permalink]

### Show Tags

let Lucy's age be L and sam's age be S
as given,
L-S=a -- 1
L+S=z --2

L= (a+z)/2
EMPOWERgmat Instructor V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15975
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: The positive difference between Sam and Lucy’s ages is a, and the sum  [#permalink]

### Show Tags

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

GMAT assassins aren't born, they're made,
Rich
_________________
Intern  Joined: 27 Oct 2015
Posts: 24
Re: The positive difference between Sam and Lucy’s ages is a, and the sum  [#permalink]

### Show Tags

L > S
L - S = a
L + S = z

2L = a + z
Hence D
Target Test Prep Representative V
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 9142
Location: United States (CA)
Re: The positive difference between Sam and Lucy’s ages is a, and the sum  [#permalink]

### Show Tags

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

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button. Re: The positive difference between Sam and Lucy’s ages is a, and the sum   [#permalink] 16 Jan 2018, 17:50
Display posts from previous: Sort by

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