Find all School-related info fast with the new School-Specific MBA Forum

It is currently 04 Aug 2015, 12:54
GMAT Club Tests

Alert:

GMAT Club Expert Essay Review: Submit Yours Here


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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

One kilogram of a certain coffee blend consists of x

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
2 KUDOS received
Intern
Intern
avatar
Joined: 30 Nov 2011
Posts: 31
Location: United States
GMAT 1: 700 Q47 V38
GPA: 3.54
Followers: 1

Kudos [?]: 29 [2] , given: 23

One kilogram of a certain coffee blend consists of x [#permalink] New post 25 Mar 2012, 10:23
2
This post received
KUDOS
22
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

42% (02:45) correct 58% (01:52) wrong based on 708 sessions
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8?

(1) y > 0.15

(2) C >= 7.30
[Reveal] Spoiler: OA
Expert Post
11 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 28784
Followers: 4606

Kudos [?]: 47689 [11] , given: 7130

Re: GMAT prep questions [#permalink] New post 25 Mar 2012, 10:28
11
This post received
KUDOS
Expert's post
8
This post was
BOOKMARKED
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8?

"One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee"

So, \(x+y=1\). Question: is \(x<0.8\).

(1) y > 0.15 --> \(1-x>0.15\) --> \(x<0.85\). Not sufficient.

(2) C >=7.30 --> \(C=6.5x + 8.5y\geq{7.3}\) --> \(C=6.5x + 8.5(1-x)\geq{7.3}\) --> \(2x\leq{1.2}\) --> \(x\leq{0.6}\). Sufficient.

Answer: B.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis ; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) ; 12. 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?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Expert Post
3 KUDOS received
Verbal Forum Moderator
Verbal Forum Moderator
User avatar
Status: Preparing for the another shot...!
Joined: 03 Feb 2011
Posts: 1422
Location: India
Concentration: Finance, Marketing
GPA: 3.75
Followers: 150

Kudos [?]: 846 [3] , given: 62

GMAT ToolKit User Premium Member
Re: GMAT prep questions [#permalink] New post 05 Feb 2013, 01:17
3
This post received
KUDOS
Expert's post
I tried doing this via using the concept of weighted average.
Its given in statement 2 that 6.5x + 8.5y>=7.3.
Now, when x=.5 and y=.5, then the c would be 7.5. (GIVEN FACT IS THAT X+Y=1.)
Total distance in terms of parts is 2 units and in terms of numerical distance is 1. For every 2 part change, there is a 0.1 deviation in the numerical separation.
Since c>=7.3( note the 0.2 deviation), the numerical deviation is 0.1. Hence x must be <=0.6.
Regards.
_________________

Prepositional Phrases Clarified|Elimination of BEING| Absolute Phrases Clarified
Rules For Posting
www.Univ-Scholarships.com

1 KUDOS received
Manager
Manager
User avatar
Joined: 07 May 2012
Posts: 76
Location: United States
Followers: 3

Kudos [?]: 74 [1] , given: 23

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 01 May 2013, 15:39
1
This post received
KUDOS
x+y=1
c= 6.5x + 8.5y
Question ---- is x<0.8 ?

As seen from above equations , for a given sum of x and y ( =1) , the value of C increases as x decreases and Y increases ( since y is multipled by greater number than x)

If x=0.8 , then y=0.2
and C= (6.5*0.8) + (8.5*0.2) = 6.9 .

Now if we increase value of x above 0.8 , the value of C decreases below 6.9 ( consider x=0.9 , then y would be 0.1 , which pulls down the value of C below 6.9--- as per the highlighted text above).
And if we decrease the value of x below 0.8 , the value of c increases from 6.9 ( cos y is increased when x is reduced).

Statement 1 - y>0.15 , Y could be 0.2 , in which case x=0.8 ( No to the answer)
or Y = 0.3 , in which case x=0.7 ( yes to the answer)
Insufficient

Statement 2 C>=7.5 , as seen from above , for any c > 6.9 demands a x <0.8 . Hence sufficient.

Hope that helps
Jyothi
_________________

Jyothi hosamani

Intern
Intern
avatar
Joined: 02 May 2013
Posts: 4
Followers: 0

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

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 03 May 2013, 20:29
It is really nice to find this place as it is full of fun. Looking forward for new friends. Hope I'll definitely enjoy my stay here.
ood question and quite a learning...

Out of curiousity, can this sum be solved in less than 2mins that too under "GMAT exam" conditions that too at first sight??
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 28784
Followers: 4606

Kudos [?]: 47689 [0], given: 7130

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 13 Jun 2013, 01:15
Expert's post
Bumping for review and further discussion*. Get a kudos point for an alternative solution!

*New project from GMAT Club!!! Check HERE

All DS Mixture Problems to practice: search.php?search_id=tag&tag_id=43
All PS Mixture Problems to practice: search.php?search_id=tag&tag_id=114

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis ; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) ; 12. 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?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Expert Post
3 KUDOS received
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 5758
Location: Pune, India
Followers: 1449

Kudos [?]: 7639 [3] , given: 186

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 16 Sep 2013, 02:15
3
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
imadkho wrote:
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8?

(1) y > 0.15

(2) C >= 7.30



Responding to a pm:
Quote:
I could solve most of the problems using the scale method, though I was finding it difficult to solve this particular question using it.


C = Avg cost of the mix = Cost of the blend = 6.5x + 8.5y

If you remember your weighted average formula, Avg = (C1*w1 + C2*w2)/(w1 + w2) =
Avg Cost = (C1*x + C2*y)/(x + y)
(x+y) is 1 kg since the weight of the blend is 1 kg.
Avg Cost = C = (C1*x + C2*y) = (6.5x + 8.5y)
So cost of type I coffee is $6.5/kg and cost of type II coffee is $8.5/kg.

So everything is set for you. All you have to do is plug in the values of x and y now.
Question: Is x > 0.8?

(1) y > 0.15
If y is 0.16, x is 0.84
If y is 0.5, x is 0.5
This statement alone is not sufficient.

(2) C >= 7.30
Let's say C = 7.3
x/y = (8.5 - 7.3)/(7.3 - 6.5) = 12/8 = 3/2 (The Scale Method)
x = 3/5 = 0.6
If C is greater than 7.3, x/y will get smaller and hence the value of x will keep getting smaller too. Say if C = 7.5,
x/y = 1/1
x = 0.5
and so on...

So x can be at most 0.6. Hence it must be less than 0.8.
Statement II alone is sufficient.

Answer (B)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

1 KUDOS received
Intern
Intern
avatar
Joined: 28 Mar 2012
Posts: 6
Location: Yugoslavia
Concentration: Accounting, Finance
GMAT 1: 650 Q V
GPA: 3.75
Followers: 0

Kudos [?]: 8 [1] , given: 21

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 16 Sep 2013, 03:15
1
This post received
KUDOS
Idk, in my opinion after you figure out that x+y=1 and that C=6.5x+8.5y (knowing that C can be 7.30), we have two equations and we can solve for X.
Please correct me if I'm wrong but this was my line of reasoning and I've chosen B after 1min. :)
1 KUDOS received
Intern
Intern
avatar
Joined: 09 Jul 2012
Posts: 11
Followers: 0

Kudos [?]: 2 [1] , given: 6

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 18 Sep 2013, 11:15
1
This post received
KUDOS
one kilogram of a certain coffee blend consists of X kilogram of type I and Y kilogram of type II" means that X+Y=1
Combined C=6.5X+8.5Y,

we get:
X=(8.5-C)/2, Y=(C-6.5)/2
Combined C>=7.3, X=(8.5-C)/2<1.2/2=0.6

Answer is B
Manager
Manager
avatar
Joined: 21 Aug 2013
Posts: 114
Schools: ISB '15
Followers: 2

Kudos [?]: 15 [0], given: 57

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 28 Nov 2013, 08:10
@Bunuel,
You are just great!!!
_________________

Veritas Prep - 650
MGMAT 1 590
MGMAT 2 640 (V48/Q31)

Please help the community by giving Kudos.

Intern
Intern
avatar
Joined: 14 Jul 2013
Posts: 32
Followers: 0

Kudos [?]: 8 [0], given: 39

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 21 Apr 2014, 00:09
Initially I got the answer wrong but there was a calculation mistake. I am posting my approach anyway :D,

Question Says,
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8?

(1) y > 0.15

(2) C >= 7.30

Sol. x + y = 1 (from question statement)
now, cost C = 6.5x + 8.5y = 6.5 (x + y) + 2y = 6.5 +2y------(eq. 1)
we need to check whether x < 0.8
or y > 0.2 (since x + y = 1)

option 1). y > 0.15
clearly not sufficient alone.

option 2). C >= 7.30
from eq.1, 6.5 + 2y >= 7.30
=> 2y => 0.80
=> y>= 0.40 or x =< 0.60
Hence, sufficient.
Intern
Intern
avatar
Joined: 12 Jan 2015
Posts: 4
Followers: 0

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

One kilogram of a certain coffee blend consists of x [#permalink] New post 12 Jan 2015, 04:22
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8?

(1) y > 0.15

(2) C >= 7.30
Manager
Manager
User avatar
Joined: 22 Oct 2014
Posts: 88
Concentration: General Management, Sustainability
GMAT 1: 770 Q50 V45
GPA: 3.8
WE: General Management (Consulting)
Followers: 0

Kudos [?]: 42 [0], given: 4

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 12 Jan 2015, 04:43
With x+y = 1, we can simplify the equation for C:

C = 6.5 + 2y

Statement 1: Not sufficient. x can still be anywhere between 0 and 0.85

Statement 2: Sufficient:
7.3 = 6.5 + 2y. This leads to y = 0.4 and x smaller than 0.8. If C is greater than 7.3, this will only increase y and therefore decrease x, which will therefore be smaller than 0.8 in any case.

Answer B.
_________________

\(\sqrt{-1}\) \(2^3\) \(\Sigma\) \(\pi\) ... and it was delicious!


Please consider giving +1 Kudos if deserved!

Intern
Intern
avatar
Joined: 12 Jan 2015
Posts: 4
Followers: 0

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

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 12 Jan 2015, 04:48
Hi littlewarthog
Thanks for your reply :lol:
Manager
Manager
avatar
Joined: 31 Jul 2014
Posts: 84
GMAT 1: 630 Q48 V29
Followers: 0

Kudos [?]: 19 [0], given: 346

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 12 Jan 2015, 05:21
superjohn5566 wrote:
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8?

(1) y > 0.15

(2) C >= 7.30


Hi
Can someone please explain the solution?

Thanks
Anupama
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 28784
Followers: 4606

Kudos [?]: 47689 [0], given: 7130

Re: One kilogram of a certain coffee blend consists of x [#permalink] New post 12 Jan 2015, 06:00
Expert's post
superjohn5566 wrote:
One kilogram of a certain coffee blend consists of x kilogram of type I coffee and y kilogram of type II coffee. The cost of the blend is C dollars per kilogram, where C = 6.5x + 8.5y. Is x < 0.8?

(1) y > 0.15

(2) C >= 7.30


Merging similar topics. Please refer to the solutions above.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis ; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) ; 12. 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?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Re: One kilogram of a certain coffee blend consists of x   [#permalink] 12 Jan 2015, 06:00
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic A certain one-day seminar consisted of a morning session and Stiv 3 09 Jul 2012, 02:31
8 Experts publish their posts in the topic One kilogram of a certain coffee blend consists of x nusmavrik 5 29 Sep 2010, 02:25
22 Experts publish their posts in the topic Lindsay can paint 1/x of a certain room in one hour Jinglander 21 08 Aug 2010, 12:46
25 Experts publish their posts in the topic A certain one-day seminar consisted of a morning session and adarsh12345 17 12 Nov 2009, 07:59
8 A certain list consists of five different integers. Is the boubi 9 20 Jul 2007, 02:19
Display posts from previous: Sort by

One kilogram of a certain coffee blend consists of x

  Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group and phpBB SEO

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®.