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

It is currently 17 Jan 2019, 00:58

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.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • The winning strategy for a high GRE score

     January 17, 2019

     January 17, 2019

     08:00 AM PST

     09:00 AM PST

    Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
  • Free GMAT Strategy Webinar

     January 19, 2019

     January 19, 2019

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

How many gallons of milk that is 10 percent butter-fat must

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

Hide Tags

 
Director
Director
avatar
Joined: 29 Nov 2012
Posts: 758
How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 03 Sep 2013, 05:35
6
4
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

85% (01:51) correct 15% (02:10) wrong based on 330 sessions

HideShow timer Statistics

How many gallons of milk that is 10 percent butter-fat must be added to 8 gallons of milk that is 35 percent butterfat to obtain milk that is 20 percent butterfat?

a) 6
b) 12
c) 14
d) 16
e) 28

Please provide detailed explanations!
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52182
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 03 Sep 2013, 05:39
5
1
fozzzy wrote:
How many gallons of milk that is 10 percent butter-fat must be added to 8 gallons of milk that is 35 percent butterfat to obtain milk that is 20 percent butterfat?

a) 6
b) 12
c) 14
d) 16
e) 28

Please provide detailed explanations!


Equate the fat:

0.1x + 0.35*8 = 0.2(x + 8) --> x = 12.

Answer: B.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | 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

General Discussion
Director
Director
avatar
Joined: 29 Nov 2012
Posts: 758
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 03 Sep 2013, 05:44
I Messed up the equations. Thanks for the quick reply!
Manager
Manager
avatar
Joined: 23 May 2013
Posts: 104
GMAT ToolKit User
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 19 Jan 2014, 05:30
would this be a 600-700 question?
_________________

“Confidence comes not from always being right but from not fearing to be wrong.”

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 52182
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 19 Jan 2014, 08:55
Intern
Intern
avatar
Joined: 22 Jan 2014
Posts: 3
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 24 Jan 2014, 07:03
Bunuel wrote:
fozzzy wrote:
How many gallons of milk that is 10 percent butter-fat must be added to 8 gallons of milk that is 35 percent butterfat to obtain milk that is 20 percent butterfat?

a) 6
b) 12
c) 14
d) 16
e) 28

Please provide detailed explanations!


Equate the fat:

0.1x + 0.35*8 = 0.2(x + 8) --> x = 12.

Answer: B.


Thanks. This is so easy with these equations! I was trying to solve this using weighted averages formula and end up with 15:10 = 8:x => x = 4/3 How can this be solved using the weighted average formula?
Intern
Intern
avatar
Joined: 05 Feb 2014
Posts: 42
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 09 May 2014, 11:23
2
For guys looking to solve by allegation

10% ............... 35%

........... 20% ..........

15% ................ 10%


\(15/10 = 3/2\) ->> \(3/2 * 8 = 12\)
Senior Manager
Senior Manager
User avatar
Status: The Final Countdown
Joined: 07 Mar 2013
Posts: 283
Concentration: Technology, General Management
GMAT 1: 710 Q47 V41
GPA: 3.84
WE: Information Technology (Computer Software)
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 15 Dec 2014, 04:17
Where can allegation concepts be learnt?It seems easier and faster than setting up equations..
Director
Director
User avatar
G
Joined: 23 Jan 2013
Posts: 560
Schools: Cambridge'16
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 14 Mar 2015, 02:53
10%-------------20%-----------35%

10x=15*8

10x=120 => x=12

B
CEO
CEO
User avatar
P
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2722
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Reviews Badge
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 29 Aug 2016, 09:53
fozzzy wrote:
How many gallons of milk that is 10 percent butter-fat must be added to 8 gallons of milk that is 35 percent butterfat to obtain milk that is 20 percent butterfat?

a) 6
b) 12
c) 14
d) 16
e) 28

Please provide detailed explanations!


Fat of First Solution + Fat of second Solution = Fat of Final Mixture

(10/100)*x + (35/100)*8 = (20/100)*(x+8)

i.e. 10x + 280 = 20x + 160

i.e. 10x = 120

i.e. x = 12

Answer: Option B
_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

CEO
CEO
User avatar
D
Joined: 11 Sep 2015
Posts: 3326
Location: Canada
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 20 Mar 2018, 07:14
Top Contributor
fozzzy wrote:
How many gallons of milk that is 10 percent butter-fat must be added to 8 gallons of milk that is 35 percent butterfat to obtain milk that is 20 percent butterfat?

a) 6
b) 12
c) 14
d) 16
e) 28


One option is to focus on the butter fat

We begin with 8 gallons of milk that is 35 percent butter-fat
So, the volume of butter fat = 35% of 8
= (0.35)(8)
= 2.8 gallons of butter fat (to begin)

Let x = number of gallons of milk that is 10 percent butter-fat to be added to the initial 8 gallons
The volume of butter fat = 10% of x
= 0.1x gallons of butter fat (to be added)

So, in the RESULTING mixture, we have:
Total volume of butter fat = 2.8 + 0.1x
TOTAL VOLUME of mixture = 8 + x

We want the RESULTING mixture to be 20 percent butter-fat
In other words, we want: (Total volume of butter fat)/(TOTAL VOLUME of mixture) = 20%
We can now write: (2.8 + 0.1x)/(8 + x) = 20/100
Cross multiply to get: 100(2.8 + 0.1x) = 20(8 + x)
Expand: 280 + 10x = 160 + 20x
Rearrange: 120 = 10x
Solve: x = 12

Answer: B

RELATED VIDEO

_________________

Test confidently with gmatprepnow.com
Image

Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2830
Re: How many gallons of milk that is 10 percent butter-fat must  [#permalink]

Show Tags

New post 21 Mar 2018, 15:19
fozzzy wrote:
How many gallons of milk that is 10 percent butter-fat must be added to 8 gallons of milk that is 35 percent butterfat to obtain milk that is 20 percent butterfat?

a) 6
b) 12
c) 14
d) 16
e) 28


We add x gallons of 10% butterfat milk to 8 gallons of 35% butterfat milk, and we obtain (x + 8) gallons of 20% butterfat milk. We can express this in an equation as:

0.1x + 0.35(8) = 0.2(x + 8)

0.1x + 2.8 = 0.2x + 1.6

1.2 = 0.1x

12 = x

Answer: B
_________________

Jeffery Miller
Head of GMAT Instruction

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

GMAT Club Bot
Re: How many gallons of milk that is 10 percent butter-fat must &nbs [#permalink] 21 Mar 2018, 15:19
Display posts from previous: Sort by

How many gallons of milk that is 10 percent butter-fat must

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


Copyright

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

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

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®.