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

It is currently 16 Oct 2018, 00:54

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

If Amberly wants to create a 40% saline solution combining solution A,

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

Hide Tags

VP
VP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1265
Location: India
Concentration: International Business, Operations
GMAT 1: 480 Q38 V22
GPA: 3.01
WE: Engineering (Consulting)
Premium Member Reviews Badge CAT Tests
If Amberly wants to create a 40% saline solution combining solution A,  [#permalink]

Show Tags

New post 29 Dec 2017, 09:56
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

74% (01:23) correct 26% (01:13) wrong based on 73 sessions

HideShow timer Statistics

If Amberly wants to create a 40% saline solution combining solution A, which is an 18% saline solution and solution B, which is a 72% saline solution, what must the ratio of the volumes of solution A to solution B be to create a 40% saline solution?

a. 1/2
b. 11/16
c. 3/4
d. 1
e. 16/11

_________________

"Do not watch clock; Do what it does. KEEP GOING."

Manager
Manager
User avatar
S
Joined: 23 May 2017
Posts: 248
Concentration: Finance, Accounting
WE: Programming (Energy and Utilities)
Re: If Amberly wants to create a 40% saline solution combining solution A,  [#permalink]

Show Tags

New post 29 Dec 2017, 10:06
0.40 ( x + y) = 0.18x + 0.72y

40x + 40y = 18x + 72y

22x = 32y

\(\frac{x}{y}\) = \(\frac{16}{11}\) = E
_________________

If you like the post, please award me Kudos!! It motivates me

Senior SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 2033
Premium Member CAT Tests
If Amberly wants to create a 40% saline solution combining solution A,  [#permalink]

Show Tags

New post 29 Dec 2017, 11:07
QZ wrote:
If Amberly wants to create a 40% saline solution combining solution A, which is an 18% saline solution and solution B, which is a 72% saline solution, what must the ratio of the volumes of solution A to solution B be to create a 40% saline solution?

a. 1/2
b. 11/16
c. 3/4
d. 1
e. 16/11

Expanding just a bit on Leo8 's good post above.

When asked for a ratio of two solutions in a resultant mixture, you can use two variables and simply find their amounts in relation to one another.

One iteration of a weighted average equation here is
(Concentration of A)(Vol A) + (Concen of B)(Vol B) = (Desired Concen)(Total vol = A+B)

"Concentration" here = percent saline

A = the 18% saline solution
B = the 72% saline solution
A + B = total volume of resultant solution
Desired concentration of saline in resultant solution is 40%

.18(A) + .72(B) = .40(A + B)
18A + 72B = 40A + 40B
32B = 22A

Ratio of A to B?
\(\frac{A}{B} = \frac{32}{22}=\frac{16}{11}\), or

16 : 11

Answer E
_________________

The only thing more dangerous than ignorance is arrogance.
-- Albert Einstein

Manager
Manager
User avatar
P
Joined: 13 Jun 2012
Posts: 189
Location: United States
WE: Supply Chain Management (Computer Hardware)
GMAT ToolKit User CAT Tests
Re: If Amberly wants to create a 40% saline solution combining solution A,  [#permalink]

Show Tags

New post 30 Dec 2017, 05:23
The best way to do this is by alligation method.

We have A=18 and B=72
combine=40
72-40=32 and 40-18=22

32:22= 16/11. Answer E
Manhattan Prep Instructor
User avatar
G
Joined: 04 Dec 2015
Posts: 629
GMAT 1: 790 Q51 V49
GRE 1: Q170 V170
Re: If Amberly wants to create a 40% saline solution combining solution A,  [#permalink]

Show Tags

New post 30 Dec 2017, 14:21
QZ wrote:
If Amberly wants to create a 40% saline solution combining solution A, which is an 18% saline solution and solution B, which is a 72% saline solution, what must the ratio of the volumes of solution A to solution B be to create a 40% saline solution?

a. 1/2
b. 11/16
c. 3/4
d. 1
e. 16/11


If you mix the two solutions equally, you'll end up with a solution that's exactly halfway between them. The halfway point between 18% and 72% is 45%.

Image

(By the way, I figured that out by averaging 18 and 72. (18 + 72)/2 = 90/2 = 45.)

So, we don't want a 1:1 ratio. (D) is out.

In order to make a solution with less than 45% saline, you'd need more of the 18% solution. Since a 1:1 ratio of the solutions will have too much saline, then there must be more 18% solution than 72% solution.

The only answer with this property is (E).
_________________

Image

Chelsey Cooley | Manhattan Prep Instructor | Seattle and Online

My upcoming GMAT trial classes | GMAT blog archive

e-GMAT Representative
User avatar
P
Joined: 04 Jan 2015
Posts: 2063
Re: If Amberly wants to create a 40% saline solution combining solution A,  [#permalink]

Show Tags

New post 31 Dec 2017, 09:54
QZ wrote:
If Amberly wants to create a 40% saline solution combining solution A, which is an 18% saline solution and solution B, which is a 72% saline solution, what must the ratio of the volumes of solution A to solution B be to create a 40% saline solution?

a. 1/2
b. 11/16
c. 3/4
d. 1
e. 16/11


Method : Using Alligation



Final Solution Saline Concentration : 40 %

Initial Solution A Saline Concentration : 18%

Initial Solution B Saline Concentration : 72%


Ratio of A : B = (72 - 40) : ( 40 - 18) = 32 : 22 = 16 : 11

Thus, the correct answer is Option E.


Regards,
Saquib
e-GMAT
Quant Expert
_________________








Register for free sessions
Number Properties | Algebra |Quant Workshop

Success Stories
Guillermo's Success Story | Carrie's Success Story

Ace GMAT quant
Articles and Question to reach Q51 | Question of the week

Must Read Articles
Number Properties – Even Odd | LCM GCD | Statistics-1 | Statistics-2
Word Problems – Percentage 1 | Percentage 2 | Time and Work 1 | Time and Work 2 | Time, Speed and Distance 1 | Time, Speed and Distance 2
Advanced Topics- Permutation and Combination 1 | Permutation and Combination 2 | Permutation and Combination 3 | Probability
Geometry- Triangles 1 | Triangles 2 | Triangles 3 | Common Mistakes in Geometry
Algebra- Wavy line | Inequalities

Practice Questions
Number Properties 1 | Number Properties 2 | Algebra 1 | Geometry | Prime Numbers | Absolute value equations | Sets



| '4 out of Top 5' Instructors on gmatclub | 70 point improvement guarantee | www.e-gmat.com

GMAT Club Bot
Re: If Amberly wants to create a 40% saline solution combining solution A, &nbs [#permalink] 31 Dec 2017, 09:54
Display posts from previous: Sort by

If Amberly wants to create a 40% saline solution combining solution A,

  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®.