Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 39725

At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
15 Oct 2012, 04:41
Question Stats:
69% (01:00) correct
31% (01:05) wrong based on 844 sessions
HideShow timer Statistics



Math Expert
Joined: 02 Sep 2009
Posts: 39725

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
15 Oct 2012, 04:41
2
This post received KUDOS
Expert's post
4
This post was BOOKMARKED
SOLUTIONAt a certain picnic, each of the guests was served either a single scoop or a double scoop icecream. How many of the guests were served a double scoop of icecream?(1) At the picnic, 60 percent of the guests were served a double scoop of icecream > \(\frac{x}{y}=\frac{4}{6}=\frac{2}{3}\), where \(x\) is the # of people served single scoop and \(y\) the # of people served double scoop. Clearly insufficient to calculate single numerical value of \(y\). (2) A total of 120 scoops of icecream were served to all the guests at the picnic > \(1*x+2*y=120\). Again not sufficient. (1)+(2) \(x=\frac{2}{3}y\) and \(x+2y=120\): we have 2 distinct linear equations with 2 unknowns, hence we can solve for \(x\) and \(y\). Sufficient. (Just to illustrate: \(\frac{2}{3}y+2y=120\) > \(y=45\)) Answer: C.
_________________
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? Extrahard Quant Tests with Brilliant Analytics



Director
Joined: 24 Aug 2009
Posts: 503
Schools: Harvard, Columbia, Stern, Booth, LSB,

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
15 Oct 2012, 05:12
2
This post received KUDOS
Let the total number of guests be 100x 1) 60x , where x can be anything >Insufficient 2) Clearly insufficient 1+2) No of guests who are served single scoop = 40x No of guests who are served double scoop = 60x Total no of scoops served  40x (1) + 60x(2) = 160x Total no of scoops served is 120 Thus 120 = 160x We can get Unique value of 60x which will 60x (120/160) = 45 >Sufficient Answer C
_________________
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



Moderator
Joined: 02 Jul 2012
Posts: 1223
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
15 Oct 2012, 08:57
2
This post received KUDOS
1) Only a percentage is given. Nothing can be said from that. 60% of 10 is 6. 60% of 100 is 60 and so on. 2)Only total number of scoops served is given. It can be 50 ppl double scoop, 20 ppl single scoop or 40 ppl double scoop, 40 ppl single scoop and so on. 1 & 2 together 2*.6*x + 1*.4*x = 120 One equation, one unknown. Easily solvable. Hence answer is C 1.6*x = 120 x = 75 So. no. of ppl to whom double scoop was served = .6*75 = 45
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Moderator
Joined: 01 Sep 2010
Posts: 3214

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
15 Oct 2012, 14:51
1
This post received KUDOS
without any calculation we can solve DS (in this precise scenario) To have a solution we need total of the guests AND a % or a ratio or something to make the information manageable. otherwise we can't solve 1) we have a % but nothing else. insuff 2) we have the total but nothing else. insuff Together we have what we are looking for C \(must\) be the answerWe could save precious seconds for other questions, tougher.
_________________
COLLECTION OF QUESTIONS AND RESOURCES Quant: 1. ALL GMATPrep questions Quant/Verbal 2. Bunuel Signature Collection  The Next Generation 3. Bunuel Signature Collection ALLINONE WITH SOLUTIONS 4. Veritas Prep Blog PDF Version 5. MGMAT Study Hall Thursdays with Ron Quant Videos Verbal:1. Verbal question bank and directories by Carcass 2. MGMAT Study Hall Thursdays with Ron Verbal Videos 3. Critical Reasoning_Oldy but goldy question banks 4. Sentence Correction_Oldy but goldy question banks 5. Readingcomprehension_Oldy but goldy question banks



Manager
Joined: 21 Sep 2012
Posts: 236

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
16 Oct 2012, 05:22
2
This post received KUDOS
statement one we know the following double scoop = 0.60 X single scoop = 0.40 X no other information insufficient
statement 2 we are given the total and no other info again insufficient
combining 1 and 2
2*0.60X +0.40X = 120 1.20X +0.40X = 120 1.60X = 120 x=120/1.6 = 75
sufficient we didn't need to do the above steps we know there was 1 unknown and 1 equation
Answer is C



Director
Status: Done with formalities.. and back..
Joined: 15 Sep 2012
Posts: 640
Location: India
Concentration: Strategy, General Management
Schools: Olin  Wash U  Class of 2015
WE: Information Technology (Computer Software)

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
16 Oct 2012, 06:19
1
This post received KUDOS
Statement 1: Double scoop , D = 60% of Total, T => Single scoop, S= 40% of T => D/S=3/2 and D+S =T Not suff to find T. Statement 2: 2D +S =120 Not suff to find T. However combining two statements we have 2 equations to find S and D. And hence we can find T. Ans C. Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectAt a certain picnic, each of the guests was served either a single scoop or a double scoop of ice cream. How many of the guests were served a double scoop of ice cream? (1) At the picnic, 60 percent of the guests were served a double scoop of ice cream. (2) A total of 120 scoops of ice cream were served to all the guests at the picnic. Practice Questions Question: 61 Page: 280 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a solution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you!
_________________
Lets Kudos!!! Black Friday Debrief



Senior Manager
Joined: 06 Aug 2011
Posts: 400

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
16 Oct 2012, 12:18
1
This post received KUDOS
120*.60 is out ans.. its C..
_________________
Bole So Nehal.. Sat Siri Akal.. Waheguru ji help me to get 700+ score !



Math Expert
Joined: 02 Sep 2009
Posts: 39725

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
19 Oct 2012, 05:07
SOLUTIONAt a certain picnic, each of the guests was served either a single scoop or a double scoop icecream. How many of the guests were served a double scoop of icecream?(1) At the picnic, 60 percent of the guests were served a double scoop of icecream > \(\frac{x}{y}=\frac{4}{6}=\frac{2}{3}\), where \(x\) is the # of people served single scoop and \(y\) the # of people served double scoop. Clearly insufficient to calculate single numerical value of \(y\). (2) A total of 120 scoops of icecream were served to all the guests at the picnic > \(1*x+2*y=120\). Again not sufficient. (1)+(2) \(x=\frac{2}{3}y\) and \(x+2y=120\): we have 2 distinct linear equations with 2 unknowns, hence we can solve for \(x\) and \(y\). Sufficient. (Just to illustrate: \(\frac{2}{3}y+2y=120\) > \(y=45\)) Answer: C. Kudos points given to everyone with correct solution. Let me know if I missed someone.
_________________
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? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 08 Jun 2013
Posts: 4

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
23 Oct 2013, 05:25
What is the problem with my equation? What did I miss? A) Is clearly insufficient But for B) I tried this: 120 = 2*(0,6*x)+1*(0,4*x) With x being the # of people who had ice cream.



Math Expert
Joined: 02 Sep 2009
Posts: 39725

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
23 Oct 2013, 06:49



Intern
Joined: 08 Jun 2013
Posts: 4

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
23 Oct 2013, 07:25
1
This post received KUDOS
Yes, thank you. I was lacking in concentration.



Current Student
Joined: 04 Aug 2013
Posts: 30
Concentration: Finance, Real Estate
GPA: 3.23
WE: Consulting (Real Estate)

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
04 Feb 2014, 18:20
What if there was 100 people at the party, then 60 people get a double scoop (so 120 scoops are given out), and 0 people get single scoops? Based on this my answer was E since the problem states that people are served EITHER a single scoop OR double scoop. How can you answer this question without knowing how many people are at the party?



Math Expert
Joined: 02 Sep 2009
Posts: 39725

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
05 Feb 2014, 01:43
HCalum11 wrote: What if there was 100 people at the party, then 60 people get a double scoop (so 120 scoops are given out), and 0 people get single scoops? Based on this my answer was E since the problem states that people are served EITHER a single scoop OR double scoop. How can you answer this question without knowing how many people are at the party? This case is not possible because it violates info given in the stem: each of the guests was served either a single scoop or a double scoop icecream. As for the # of the guests, we can get it when we combine the statements: 30 of the guests were served a single scoop of icecream; 45 of the guests were served a double scoop of icecream. Total = 30 + 45 = 75 guests. For more check here: atacertainpicniceachoftheguestswasservedeithera140734.html#p1131491Hope it 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? Extrahard Quant Tests with Brilliant Analytics



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 16014

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
08 Feb 2015, 18:21
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Director
Joined: 10 Mar 2013
Posts: 597
Location: Germany
Concentration: Finance, Entrepreneurship
GPA: 3.88
WE: Information Technology (Consulting)

At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
24 May 2015, 04:06
First theory (from MGMAT) Concrete valueIf a Data Sufficiency question asks for the concrete value of one element of a ratio, you will need BOTH the concrete value of another element of the ratio AND the relative value of two elements of the ratio. Relative valueIf a Data Sufficiency question asks for the relative value of two pieces of a ratio, ANY statement that gives the relative value of ANY two pieces of the ratio will be sufficient. We can solve this question using ratiosD= # of doubleScoop portions served T= # Total portions served (1) At the picnic, 60 percent of the guests were served a double scoop of ice cream. This statement tells us that the ratio of D/T = 3/5 Not Sufficient (See explanation above  we are asked to find the concrete Value) (2) A total of 120 scoops of ice cream were served to all the guests at the picnic. Not sufficient because we need add. a ratio od D/T to answer this question (1+2) D/S = 3/5 so we have 3x+5x = 120 X = 15 > D=3*15 =45 (C) Correct, can be calculated, BUT if you know the theory you don't need to calculate by DS Questions, it's enoough to know whether it can be calculated or not. Hope this helps
_________________
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



GMAT Club Legend
Joined: 09 Sep 2013
Posts: 16014

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
28 Jun 2016, 00:20
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Books  GMAT Club Tests  Best Prices on GMAT Courses  GMAT Mobile App  Math Resources  Verbal Resources



Senior Manager
Joined: 08 Dec 2015
Posts: 304

Re: At a certain picnic, each of the guests was served either a [#permalink]
Show Tags
07 Jan 2017, 16:44
Why not do:
1)3/5(total)=double
2)total=120
1)+2) sufficient.
Am I oversimplifying this?




Re: At a certain picnic, each of the guests was served either a
[#permalink]
07 Jan 2017, 16:44







