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

It is currently 23 May 2019, 10:11

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

Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres

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

Hide Tags

 
Manager
Manager
User avatar
Joined: 28 Jul 2011
Posts: 174
Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 24 Aug 2011, 05:04
16
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

76% (01:41) correct 24% (02:25) wrong based on 246 sessions

HideShow timer Statistics

Salad dressing A is made up of 30% vinegar and 70% oil, and salad dressing B contains 10% vinegar and 90% oil. If the 2 dressing are combined to produce a salad dressing that is 15% vinegar, dressing A comprises what % of the new dressing?

A. 15%
B. 20%
C. 25%
D. 40%
E. 55%
Most Helpful Expert Reply
CEO
CEO
User avatar
B
Joined: 17 Nov 2007
Posts: 3408
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
GMAT ToolKit User
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 24 Aug 2011, 07:07
2
5
There is one trick you can use to solve mixture problems very fast.

quantity of Vinegar in A: 30%, in B: 10% and in (A+B): 15%

We need (15-10)/(30-10) = 5/20 = 1/4 or 25% of A.
_________________
HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | Limited GMAT/GRE Math tutoring in Chicago
General Discussion
Manager
Manager
avatar
Joined: 27 Jul 2010
Posts: 71
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 24 Aug 2011, 06:53
3
1
they way I solved it:
quantity of Vinegar => 30% A + 10% B = 15% (A + B)
30%A + 10%B = 15%A + 15%B
15%A = 5%B
B = 15%A / 5% = 3A
if B = 3A => A+B = 4A
as a result A / (A+B) = A / 4A = 0.25 = 25%
Manager
Manager
avatar
Joined: 24 Nov 2010
Posts: 173
Location: United States (CA)
Concentration: Technology, Entrepreneurship
Schools: Ross '15, Duke '15
GMAT ToolKit User
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 24 Aug 2011, 07:13
use the graph method to solve it quickly

B has 30% vinegar, A - 10% and the new dressing - 15%
---10-----15-----------------30
therefore intuitively you can say that there is a lot less of dressing A than dressing B in the new mix since 15 is closer to 10 than 30 is. How much lesser? (15-10)/(30-10) = 5/20 = 25%
Manager
Manager
User avatar
Joined: 04 Apr 2010
Posts: 132
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 24 Aug 2011, 12:05
3
The total combination must be 100%. Let X% of dressing 1 is used.
30 * x + 10 * (100-x) = 15*100
solving, x= 25%
C is the answer.
_________________
Consider me giving KUDOS, if you find my post helpful.
If at first you don't succeed, you're running about average. ~Anonymous
Manager
Manager
User avatar
Joined: 28 Jul 2011
Posts: 174
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 25 Aug 2011, 05:23
Thank everyone, appreciate your help. those were some really good short hands.

Regards,
Manager
Manager
avatar
Joined: 19 Oct 2010
Posts: 162
Location: India
GMAT 1: 560 Q36 V31
GPA: 3
GMAT ToolKit User
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 08 Sep 2011, 09:59
alexgmd wrote:
they way I solved it:
quantity of Vinegar => 30% A + 10% B = 15% (A + B)
30%A + 10%B = 15%A + 15%B
15%A = 5%B
B = 15%A / 5% = 3A
if B = 3A => A+B = 4A
as a result A / (A+B) = A / 4A = 0.25 = 25%


This is how I worked it out.

Walker, can you please explain your method a bit?
_________________
petrifiedbutstanding
Veritas Prep GMAT Instructor
User avatar
D
Joined: 16 Oct 2010
Posts: 9234
Location: Pune, India
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 19 Oct 2014, 22:05
kuttingchai wrote:
Salad dressing A is made up of 30% vinegar and 70% oil, and salad dressing B contains 10% vinegar and 90% oil. If the 2 dressing are combined to produce a salad dressing that is 15% vinegar, dressing A comprises what % of the new dressing?

A. 15%
B. 20%
C. 25%
D. 40%
E. 55%


Here is a post that discusses how to solve such questions in seconds: http://www.veritasprep.com/blog/2011/04 ... -mixtures/
The copper nickel example is exactly like this one.

w1/w2 = (A2 - Aavg)/(Aavg - A1)
wA/wB = (10 - 15)/(15 - 30) = 1/3

So ratio of salad dressing A to salad dressing B is 1:3 i.e. salad dressing A makes up 1/4 = 25% of the mix.
Answer (C)
_________________
Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
Target Test Prep Representative
User avatar
G
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2823
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 22 Feb 2018, 17:34
kuttingchai wrote:
Salad dressing A is made up of 30% vinegar and 70% oil, and salad dressing B contains 10% vinegar and 90% oil. If the 2 dressing are combined to produce a salad dressing that is 15% vinegar, dressing A comprises what % of the new dressing?

A. 15%
B. 20%
C. 25%
D. 40%
E. 55%


We can let the amount of dressing A = a and the amount of dressing B = b, thus:

0.3a + 0.1b = 0.15(a + b)

30a + 10b = 15a + 15b

15a = 5b

3a = b

So dressing A is a/(a + b) = a/(a + 3a) = 1/4 = 25% of the new dressing.

Answer: C
_________________

Jeffrey Miller

Head of GMAT Instruction

Jeff@TargetTestPrep.com
TTP - Target Test Prep Logo
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.

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 11004
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres  [#permalink]

Show Tags

New post 24 Mar 2019, 23:00
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 Club Bot
Re: Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres   [#permalink] 24 Mar 2019, 23:00
Display posts from previous: Sort by

Salad dressing A is made up of 30% vinegar and 70% oil, and salad dres

  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®.