GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 20 Oct 2019, 12:22

### 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

# In the table above, what is the number of green marbles in J

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

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58434
In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

01 Oct 2012, 05:11
3
12
00:00

Difficulty:

5% (low)

Question Stats:

91% (01:45) correct 9% (02:04) wrong based on 805 sessions

### HideShow timer Statistics

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

Practice Questions
Question: 55
Page: 159
Difficulty: 600

Attachment:

Table.png [ 40.01 KiB | Viewed 18567 times ]

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 58434
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

01 Oct 2012, 05:11
4
4
SOLUTION

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

We need to find the value of $$z$$, while given that:

$$x+y=80$$;
$$y+z=120$$;
$$x+z=160$$.

Sum these 3 equations: $$2x+2y+2z=360$$ --> reduce by 2: $$x+y+z=180$$ --> since we know that $$x+y=80$$, then $$80+z=180$$ --> $$z=100$$.

_________________
##### General Discussion
Senior Manager
Joined: 31 Oct 2011
Posts: 477
Schools: Johnson '16 (M)
GMAT 1: 690 Q45 V40
WE: Asset Management (Mutual Funds and Brokerage)
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

01 Oct 2012, 05:19
2
To solve, I took the sum of the expressions as seen below:

X + Y = 80
Y + Z = 120
X + Z = 160
2X + 2Y + 2Z = 360

Dividing by 2 we get X + Y + Z = 180.

Since we know X + Y = 80 from Jar P, we can deduce that Z = 100. Since Z is the number of green marbles in Jar R we have our solution.

Answer is D, 100

_________________
My Applicant Blog: http://hamm0.wordpress.com/
Senior Manager
Joined: 24 Aug 2009
Posts: 445
Schools: Harvard, Columbia, Stern, Booth, LSB,
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

01 Oct 2012, 20:22
2
x+y = 80 ---(1)
x+z = 160---(2)
z+y= 120---(3)
Subtract equation 1 from 2 & we get--> z-y = 80----(4)
Add equation (4) & (3) we get--> 2z= 200
z=100
_________________
If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS.
Kudos always maximizes GMATCLUB worth
-Game Theory

If you have any question regarding my post, kindly pm me or else I won't be able to reply
Intern
Joined: 30 Aug 2011
Posts: 15
Location: United States
Concentration: General Management, International Business
Schools: ISB '15
GMAT 1: 680 Q46 V37
WE: Project Management (Computer Software)
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

04 Oct 2012, 00:41
1
x + y = 80 ......(1)
y + z = 120 .....(2)
x + z = 160 ......(3)

From (2) above, z=160-y .....Substitute value of z in (3)

==> x-y = 40 ....(4)

Solve (1) and (4), to get x = 60
==> y = 20
==> z = 100

Thus, number of green marbles in Jar R = 100 (Ans = D)
Math Expert
Joined: 02 Sep 2009
Posts: 58434
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

04 Oct 2012, 14:20
2
SOLUTION

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

We need to find the value of $$z$$, while given that:

$$x+y=80$$;
$$y+z=120$$;
$$x+z=160$$.

Sum these 3 equations: $$2x+2y+2z=360$$ --> reduce by 2: $$x+y+z=180$$ --> since we know that $$x+y=80$$, then $$80+z=180$$ --> $$z=100$$.

Kudos points given to everyone with correct solution. Let me know if I missed someone.
_________________
Senior Manager
Joined: 13 Aug 2012
Posts: 401
Concentration: Marketing, Finance
GPA: 3.23
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

10 Dec 2012, 04:43
1
$$x + y = 80$$ eq 1
$$y + z = 120$$ eq 2
$$x + z = 160$$ eq 3
______________
$$2x + 2y + 2z = 360 --> x + y+ z = 180$$ eq 4

Combine eq 4 and eq 1:

$$80 + z = 180 --> z = 100$$

_________________
Impossible is nothing to God.
Manager
Joined: 15 Aug 2013
Posts: 228
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

13 Apr 2014, 08:52
Bunuel wrote:
SOLUTION

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

We need to find the value of $$z$$, while given that:

$$x+y=80$$;
$$y+z=120$$;
$$x+z=160$$.

Sum these 3 equations: $$2x+2y+2z=360$$ --> reduce by 2: $$x+y+z=180$$ --> since we know that $$x+y=80$$, then $$80+z=180$$ --> $$z=100$$.

Kudos points given to everyone with correct solution. Let me know if I missed someone.

Are we always allowed to sum the 3 equations? Do we need to have some commonalities to be able to sum the equations?
Manager
Status: suffer now and live forever as a champion!!!
Joined: 01 Sep 2013
Posts: 101
Location: India
GPA: 3.5
WE: Information Technology (Computer Software)
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

13 Apr 2014, 21:16
X+Y =80 --------- (1)

Y+Z =120 -------- (2)

X+Z =160 -------- (3)

Subtract (3) -(1)

we get

Z - Y = 80 -----------(4)

ADD (4) and (2) equations,
Z=100;

Hence D.
Math Expert
Joined: 02 Sep 2009
Posts: 58434
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

14 Apr 2014, 01:30
russ9 wrote:
Bunuel wrote:
SOLUTION

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

We need to find the value of $$z$$, while given that:

$$x+y=80$$;
$$y+z=120$$;
$$x+z=160$$.

Sum these 3 equations: $$2x+2y+2z=360$$ --> reduce by 2: $$x+y+z=180$$ --> since we know that $$x+y=80$$, then $$80+z=180$$ --> $$z=100$$.

Kudos points given to everyone with correct solution. Let me know if I missed someone.

Are we always allowed to sum the 3 equations? Do we need to have some commonalities to be able to sum the equations?

Yes, we can sum/subtract/multiply equations. I think you are mixing equations with inequalities, for which there are specific rules.

Hope this helps.
_________________
Manager
Joined: 15 Aug 2013
Posts: 228
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

28 Apr 2014, 21:27
Bunuel wrote:
russ9 wrote:
Bunuel wrote:
SOLUTION

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

We need to find the value of $$z$$, while given that:

$$x+y=80$$;
$$y+z=120$$;
$$x+z=160$$.

Sum these 3 equations: $$2x+2y+2z=360$$ --> reduce by 2: $$x+y+z=180$$ --> since we know that $$x+y=80$$, then $$80+z=180$$ --> $$z=100$$.

Kudos points given to everyone with correct solution. Let me know if I missed someone.

Are we always allowed to sum the 3 equations? Do we need to have some commonalities to be able to sum the equations?

Yes, we can sum/subtract/multiply equations. I think you are mixing equations with inequalities, for which there are specific rules.

Hope this helps.

Thanks for clarifying.

Just to confirm one of your comments above -- "Yes, we can sum/subtract/multiply equations." -- would this be valid for the problem even if one of the equations didn't have any common variables. What I mean is, if the equations read:

$$x+y=80$$;
$$a+b=120$$;
$$x+z=160$$.

Can we still add the 3?
Math Expert
Joined: 02 Sep 2009
Posts: 58434
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

29 Apr 2014, 00:58
russ9 wrote:
Bunuel wrote:
russ9 wrote:
Are we always allowed to sum the 3 equations? Do we need to have some commonalities to be able to sum the equations?

Yes, we can sum/subtract/multiply equations. I think you are mixing equations with inequalities, for which there are specific rules.

Hope this helps.

Thanks for clarifying.

Just to confirm one of your comments above -- "Yes, we can sum/subtract/multiply equations." -- would this be valid for the problem even if one of the equations didn't have any common variables. What I mean is, if the equations read:

$$x+y=80$$;
$$a+b=120$$;
$$x+z=160$$.

Can we still add the 3?

_______________________
Yes.
_________________
SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1749
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

09 Sep 2014, 22:05
The table provided in this question was a boon for me. See how below.....
Attachment:

Table.png [ 45.65 KiB | Viewed 13269 times ]

1. Replaced y with (80-x). The equation remains intact on "Jar P" row

2. Copied (80-x) in "Jar Q" row.

These 2 steps directly eliminates x & y

3. Adding rows "Jar Q" & "Jar R"

2z+80 = 280

z = 100

_________________
Kindly press "+1 Kudos" to appreciate
Intern
Joined: 18 Oct 2013
Posts: 2
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

21 Nov 2014, 03:28
From the given table we could make equations like
Equation 1. Given x+y=80 ----> x=80-y
Equation2. Given y+z=120
Equation3. Given x+z = 160
Substituting the value of x in Equation 3 from Equation 1
Equation 4. (80-y)+z=160 ----> -y+z = 80
Adding Equation 2 and Equation 4
2z=200 ---> Z=100.
Senior Manager
Joined: 10 Mar 2013
Posts: 465
Location: Germany
Concentration: Finance, Entrepreneurship
Schools: WHU MBA"20 (A)
GMAT 1: 580 Q46 V24
GPA: 3.88
WE: Information Technology (Consulting)
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

22 Jul 2015, 09:52
just substract from the first equation the 2nd and the 3rd you'll get --> x+y-y-z-x-z = -200 ->x,y cancel out and Z=100 (D)
_________________
When you’re up, your friends know who you are. When you’re down, you know who your friends are.

Share some Kudos, if my posts help you. Thank you !

800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50
GMAT PREP 670
MGMAT CAT 630
KAPLAN CAT 660
Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2815
In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

30 May 2016, 05:32
Bunuel wrote:

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

We can create three equations from the information presented in the table.

Equation 1: x + y = 80

Equation 2: y + z = 120

Equation 3: x + z = 160

These equations present us with a good opportunity to use the “combination method” to solve multiple equations. Here, we can add equations together. Because we need the number of green marbles in jar R, we need to determine the value of z.

We can start by multiplying equation 1 by -1.

-1(x + y = 80) = -x – y = -80

Next, we add this equation to equation 2. So we have:

-x - y = -80 + (z + y = 120) = z – x = 40

Now we can add z – x = 40 to equation 3. So we have:

–x + z = 40 + (x + z = 160)

2z = 200

z = 100

_________________

# Jeffrey Miller

Head of GMAT Instruction

Jeff@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

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.

Manager
Joined: 18 Jan 2010
Posts: 246
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

30 May 2016, 06:03
Bunuel wrote:

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

Practice Questions
Question: 55
Page: 159
Difficulty: 600

Attachment:
Table.png

Simply add the three given details

x+y=80
y+z=120-
x+z=160

2(x+y+z) = 360
x+y+z = 180

Now We want green marbles in Jar R. That is we want z.
x+y+z=180
x+y= 80; this means z = 100
Option D is the answer.
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15294
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

22 Feb 2018, 13:38
Hi All,

Complex-"looking" prompts can often hide hidden patterns that will help you to reduce the amount of work you need to do to answer the question.

The question asks us for the number of green marbles in Jar R, so we're asked "what is the value of Z?"

In the table, you might notice that each variable shows up EXACTLY TWICE, so if we add all of the equations together, we have…

2X + 2Y + 2Z = 360

So…

X + Y + Z = 180

Notice in Jar P….X + Y = 80

Combining these two equations gives us the value of Z…..100

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
SVP
Joined: 03 Jun 2019
Posts: 1734
Location: India
Re: In the table above, what is the number of green marbles in J  [#permalink]

### Show Tags

15 Sep 2019, 06:26
Bunuel wrote:

In the table above, what is the number of green marbles in Jar R ?

(A) 70
(B) 80
(C) 90
(D) 100
(E) 110

Practice Questions
Question: 55
Page: 159
Difficulty: 600

Attachment:
Table.png

x+y+z=180
x+y=80
z=100

IMO D

Posted from my mobile device
_________________
"Success is not final; failure is not fatal: It is the courage to continue that counts."

Please provide kudos if you like my post. Kudos encourage active discussions.

My GMAT Resources: -

Efficient Learning
All you need to know about GMAT quant

Tele: +91-11-40396815
Mobile : +91-9910661622
E-mail : kinshook.chaturvedi@gmail.com
Re: In the table above, what is the number of green marbles in J   [#permalink] 15 Sep 2019, 06:26
Display posts from previous: Sort by

# In the table above, what is the number of green marbles in J

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

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