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

It is currently 22 Jul 2018, 11:43

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

What amount (in milliliters) of a 1% sulfuric acid solution must be ad

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 47183
What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 29 Mar 2018, 00:25
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

80% (01:06) correct 20% (01:31) wrong based on 64 sessions

HideShow timer Statistics

What amount (in milliliters) of a 1% sulfuric acid solution must be added to 60 milliliters of a 6% sulfuric acid solution to yield a 5% sulfuric acid solution?

(A) 12
(B) 15
(C) 18
(D) 20
(E) 45

_________________

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

Manager
Manager
User avatar
G
Joined: 16 Sep 2016
Posts: 225
WE: Analyst (Health Care)
Premium Member CAT Tests
Re: What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 29 Mar 2018, 01:27
Bunuel wrote:
What amount (in milliliters) of a 1% sulfuric acid solution must be added to 60 milliliters of a 6% sulfuric acid solution to yield a 5% sulfuric acid solution?

(A) 12
(B) 15
(C) 18
(D) 20
(E) 45


60 ml 6% sulphuric acid has \(\frac{6}{100}*60 = 3.6\) ml sulphuric acid and rest is water.

x ml of 1% sulphuric acid will have \(\frac{1}{100}*x = x/100\) ml of sulphuric acid.

so total sulphuric acid will be 3.6 + x/100 in total volume of 60 + x.

This new mixture has to be 5% sulphuric acid

Hence 5% of (60+x) = 3.6 + x/100

\(\frac{5}{100}*(60 + x) = 3.6 + \frac{x}{100}\)
\(3 + \frac{5x}{100} = 3.6 + \frac{x}{100}\)
\(\frac{4x}{100} = 0.6\)
\(x = \frac{60}{4}\)
\(x = 15\) ml

Hence Option (B) is our answer.

Best,
Gladi
Expert Post
1 KUDOS received
SVP
SVP
User avatar
P
Joined: 08 Jul 2010
Posts: 2120
Location: India
GMAT: INSIGHT
WE: Education (Education)
Reviews Badge
Re: What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 29 Mar 2018, 03:33
1
Bunuel wrote:
What amount (in milliliters) of a 1% sulfuric acid solution must be added to 60 milliliters of a 6% sulfuric acid solution to yield a 5% sulfuric acid solution?

(A) 12
(B) 15
(C) 18
(D) 20
(E) 45


TIP: For all such questions of Mixtures one must make an equation of actual quantity of one substance.

For instance here the equation can be formed on the quantity of sulfuric acid

Sulfuric acid of 60 ml solution + Sulfuric acid of 1% solution = Sulfuric acid of Final solution

i.e. (6/100)*60 + (1/100)*x = (5/100)*(60+x)

i.e. x = 15

Answer: Option B

Alternatively: One may use allegation method however I suggest that for starters and not so strong in maths should follow the method of making equation
_________________

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

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

DS Forum Moderator
User avatar
P
Joined: 27 Oct 2017
Posts: 627
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)
Premium Member CAT Tests
Re: What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 29 Mar 2018, 04:13
The best approach shall be using principle of alligation.

Principle: If two ingredients A and B of price x and y respectively are mixed and the price of resultant mixture is M (mean price)then the ratio (R) in which ingredients are mixed is given by, the rule of allegation

R=(M−y)/(x−M)

Posted from my mobile device

Posted from my mobile device
_________________

SC: Confusable words
All you need for Quant, GMAT PS Question Directory,GMAT DS Question Directory
Error log/Key Concepts
Combination Concept: Division into groups
Question of the Day (QOTD)
Free GMAT CATS

1 KUDOS received
DS Forum Moderator
User avatar
P
Joined: 27 Oct 2017
Posts: 627
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)
Premium Member CAT Tests
Re: What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 29 Mar 2018, 04:17
1
Please see the sketch for alligation approach

gmatbusters wrote:
The best approach shall be using principle of alligation.

Principle: If two ingredients A and B of price x and y respectively are mixed and the price of resultant mixture is M (mean price)then the ratio (R) in which ingredients are mixed is given by, the rule of allegation

R=(M−y)/(x−M)

Posted from my mobile device

Posted from my mobile device

Attachments

IMG_20180329_163830.jpg
IMG_20180329_163830.jpg [ 495.3 KiB | Viewed 596 times ]


_________________

SC: Confusable words
All you need for Quant, GMAT PS Question Directory,GMAT DS Question Directory
Error log/Key Concepts
Combination Concept: Division into groups
Question of the Day (QOTD)
Free GMAT CATS

VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1038
What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 29 Mar 2018, 10:01
Bunuel wrote:
What amount (in milliliters) of a 1% sulfuric acid solution must be added to 60 milliliters of a 6% sulfuric acid solution to yield a 5% sulfuric acid solution?

(A) 12
(B) 15
(C) 18
(D) 20
(E) 45


let x=amount of 1% acid to be added
.01*x+.06*60=.05(60+x)
x=15 milliliters
B
Expert Post
Target Test Prep Representative
User avatar
G
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2973
Location: United States (CA)
Re: What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 30 Mar 2018, 10:47
Bunuel wrote:
What amount (in milliliters) of a 1% sulfuric acid solution must be added to 60 milliliters of a 6% sulfuric acid solution to yield a 5% sulfuric acid solution?

(A) 12
(B) 15
(C) 18
(D) 20
(E) 45


We can let the amount of 1% sulfuric acid to be added = n and create the equation:

(0.01n + 0.06 x 60)/(60 + n) = 0.05

0.01n + 3.6 = 0.05(60 + n)

0.01n + 3.6 = 3 + 0.05n

0.6 = 0.04n

15 = n

Answer: B
_________________

Scott Woodbury-Stewart
Founder and CEO

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

SC Moderator
avatar
D
Joined: 22 May 2016
Posts: 1835
Premium Member CAT Tests
What amount (in milliliters) of a 1% sulfuric acid solution must be ad  [#permalink]

Show Tags

New post 31 Mar 2018, 11:38
Bunuel wrote:
What amount (in milliliters) of a 1% sulfuric acid solution must be added to 60 milliliters of a 6% sulfuric acid solution to yield a 5% sulfuric acid solution?

(A) 12
(B) 15
(C) 18
(D) 20
(E) 45

Let x = amount of 1% sulfuric acid to be added
A = solution with 1% sulfuric acid
B = solution with 6% sulfuric acid

(% A)(Vol A) + (% B)(Vol B) = (% of A+B)(Vol of A+B)

\(.01(x) + .06(60) = .05(x + 60)\)
Multiply all by 100 to make math quicker
\(1x + 6(60) = 5(x + 60)\)
\(1x + 360 = 5x + 300\)
\(4x = 60\)
\(x=\frac{60}{4}=15\)

Answer B
_________________

In the depths of winter, I finally learned
that within me there lay an invincible summer.

-- Albert Camus, "Return to Tipasa"

What amount (in milliliters) of a 1% sulfuric acid solution must be ad &nbs [#permalink] 31 Mar 2018, 11:38
Display posts from previous: Sort by

What amount (in milliliters) of a 1% sulfuric acid solution must be ad

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

Events & Promotions

PREV
NEXT


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®.