Author
Message
TAGS:

Hide Tags
Math Expert

Joined: 02 Sep 2009

Posts: 34855

Followers: 6483

Kudos [? ]:
82649
[0 ] , given: 10110

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

Show Tags
01 Oct 2012, 05:11
Question Stats:

90% (02:22) correct

10% (01:59) wrong

based on 609 sessions

Hide Show timer Statistics

Math Expert

Joined: 02 Sep 2009

Posts: 34855

Followers: 6483

Kudos [? ]:
82649
[2 ]
, given: 10110

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
01 Oct 2012, 05:11
2

This post received KUDOS

Expert's post

1

This post was BOOKMARKED

Current Student

Joined: 31 Oct 2011

Posts: 484

GMAT 1 : 690 Q45 V40

WE: Asset Management (Mutual Funds and Brokerage)

Followers: 38

Kudos [? ]:
216
[2 ]
, given: 57

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
01 Oct 2012, 05:19
2

This post received KUDOS

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.

_________________

My Applicant Blog: http://hamm0.wordpress.com/

Director

Joined: 24 Aug 2009

Posts: 504

Schools: Harvard, Columbia, Stern, Booth, LSB,

Followers: 15

Kudos [? ]:
636
[1 ]
, given: 241

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
01 Oct 2012, 20:22
1

This post received KUDOS

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

Answer D

_________________

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: 22

Location: United States

Concentration: General Management, International Business

GMAT 1 : 680 Q46 V37

WE: Project Management (Computer Software)

Followers: 0

Kudos [? ]:
15
[1 ]
, given: 17

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
04 Oct 2012, 00:41
1

This post received KUDOS

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: 34855

Followers: 6483

Kudos [? ]:
82649
[2 ]
, given: 10110

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
04 Oct 2012, 14:20

Manager

Joined: 25 Jun 2012

Posts: 71

Location: India

WE: General Management (Energy and Utilities)

Followers: 4

Kudos [? ]:
95
[0 ] , given: 15

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
05 Oct 2012, 03:19

x+y=80...(1) y+z=120 ==> z=120-y x+z=160 ==> z=120-x...(3) 120-x=160-y ==> x-y=40...(2) sloving (1) & (2) we get x=60 put value of x=60 in eqn (3), 60+z=160 => z=100 Ans

Senior Manager

Joined: 13 Aug 2012

Posts: 464

Concentration: Marketing, Finance

GMAT 1 : Q V0

GPA: 3.23

Followers: 25

Kudos [? ]:
394
[0 ] , given: 11

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
10 Dec 2012, 04:43

\(x + y = 80\) 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:

\(80 + z = 180 --> z = 100\)

Answer: D

_________________

Impossible is nothing to God.

Senior Manager

Joined: 15 Aug 2013

Posts: 328

Followers: 0

Kudos [? ]:
44
[0 ] , given: 23

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 \(80+z=180\) --> \(z=100\).

Answer: D.

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: 149

Location: India

Dheeraj: Madaraboina

GPA: 3.5

WE: Information Technology (Computer Software)

Followers: 0

Kudos [? ]:
52
[0 ] , given: 75

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: 34855

Followers: 6483

Kudos [? ]:
82649
[0 ] , given: 10110

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 \(80+z=180\) --> \(z=100\).

Answer: D.

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.

Adding/subtracting/multiplying/dividing inequalities: help-with-add-subtract-mult-divid-multiple-inequalities-155290.html Hope this helps.

_________________

New to the Math Forum? Please read this: 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

Joined: 15 Aug 2013

Posts: 328

Followers: 0

Kudos [? ]:
44
[0 ] , given: 23

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 \(80+z=180\) --> \(z=100\).

Answer: D.

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.

Adding/subtracting/multiplying/dividing inequalities: help-with-add-subtract-mult-divid-multiple-inequalities-155290.html 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: 34855

Followers: 6483

Kudos [? ]:
82649
[0 ] , given: 10110

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
29 Apr 2014, 00:58

Senior Manager

Joined: 15 Aug 2013

Posts: 328

Followers: 0

Kudos [? ]:
44
[0 ] , given: 23

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
29 Apr 2014, 07:47

Bunuel wrote:

russ wrote:

Can we still add the 3?

_______________________

Yes.

Thanks -- that clarifies a lot!

Senior Manager

Joined: 25 Sep 2012

Posts: 299

Location: India

Concentration: Strategy, Marketing

GMAT 1 : 660 Q49 V31GMAT 2 : 680 Q48 V34

Followers: 2

Kudos [? ]:
123
[1 ]
, given: 242

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
29 May 2014, 09:03
1

This post received KUDOS

official answer is not registered for this question.

Math Expert

Joined: 02 Sep 2009

Posts: 34855

Followers: 6483

Kudos [? ]:
82649
[0 ] , given: 10110

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
29 May 2014, 09:04

Manager

Joined: 13 Feb 2011

Posts: 104

Followers: 0

Kudos [? ]:
24
[0 ] , given: 3358

Re: In the table above, what is the number of green marbles in J [#permalink ]

Show Tags
20 Aug 2014, 23:47

Another approach can be back solving by taking a value from choices for z and finding x and y to see if they make sense per the table.

SVP

Status: The Best Or Nothing

Joined: 27 Dec 2012

Posts: 1858

Location: India

Concentration: General Management, Technology

WE: Information Technology (Computer Software)

Followers: 39

Kudos [? ]:
1709
[0 ] , given: 193

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 6063 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

Answer = D

_________________

Kindly press "+1 Kudos" to appreciate

Intern

Joined: 18 Oct 2013

Posts: 3

Followers: 0

Kudos [? ]:
0
[0 ] , given: 20

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.

Director

Joined: 10 Mar 2013

Posts: 608

Location: Germany

Concentration: Finance, Entrepreneurship

GMAT 1 : 580 Q46 V24

GPA: 3.88

WE: Information Technology (Consulting)

Followers: 9

Kudos [? ]:
199
[0 ] , given: 200

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

Re: In the table above, what is the number of green marbles in J
[#permalink ]
22 Jul 2015, 09:52

Go to page
1 2
Next
[ 23 posts ]