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

It is currently 23 Sep 2019, 04:46

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

Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog

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

Hide Tags

Find Similar Topics 
Manager
Manager
avatar
Joined: 14 Dec 2004
Posts: 105
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post Updated on: 27 Jun 2015, 06:22
17
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

73% (02:19) correct 27% (02:44) wrong based on 433 sessions

HideShow timer Statistics

Three quarts of a bleaching chemical, Minum, contains 5 percent hydrogen peroxide and water. A different type of bleaching chemical, Maxim, which contains 20 percent hydrogen peroxide, will be mixed with the three quarts of Minum. How much of type Maxim should be added to the three quarts of Minum so that the resulting mixture contains 15 percent hydrogen peroxide?

A. 3 quarts
B. 3.75 quarts
C. 4.5 quarts
D. 6 quarts
E. 9 quarts

Originally posted by cloaked_vessel on 04 Apr 2005, 11:04.
Last edited by Bunuel on 27 Jun 2015, 06:22, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58155
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 30 Jun 2015, 03:22
8
4
arshu27 wrote:
cloaked_vessel wrote:
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrogen peroxide and water. A different type of bleaching chemical, Maxim, which contains 20 percent hydrogen peroxide, will be mixed with the three quarts of Minum. How much of type Maxim should be added to the three quarts of Minum so that the resulting mixture contains 15 percent hydrogen peroxide?

A. 3 quarts
B. 3.75 quarts
C. 4.5 quarts
D. 6 quarts
E. 9 quarts


"Bunuel,

can you please explain the solution stepwise as i have no idea as to how to start this sort of mixture questions. Thanks!


Approach #1:

Minum contains 5 percent hydrogen peroxide.
Maxim contains 20 percent hydrogen peroxide.

Minum:Maxim = (20 - 15):(15 - 5) = 1:2. (Check for more here: http://www.veritasprep.com/blog/2011/04 ... -mixtures/)

So, for the final concentration to be 15% for every par of Minum we should take 2 parts of Maxim. Since, we are mixing 3 parts of Minum, we should take 3*2 = 6 parts of Maxim.

Approach #2:

Equate hydrogen peroxide:

5% of 3 parts + 20% of x parts = 15% of total, so 15% of 3 + x parts:
0.05*3 + 0.2*x = 0.15(3 + x)
x = 6.

Answer: D.

Another approach would be just to plug in the answers and work backwards.

Hope it helps.
_________________
General Discussion
Intern
Intern
avatar
Joined: 22 Mar 2008
Posts: 44
Re: Mixture bleaching chemical  [#permalink]

Show Tags

New post 29 Jul 2009, 09:21
2
2
The answer is 6.
let 'x' be the qty of maxim which has to be mixed with minum.
so, the total qty of the mixture=(x+3).
Since the mixture has 15% of hydrogen peroxide
we can have the eqn as
(5%*3)+(20%*x)=15%*(x+3)
solving this we get x=6.

hence D.
VP
VP
avatar
Joined: 30 Sep 2004
Posts: 1267
Location: Germany
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 04 Apr 2005, 13:10
1
3*0,05+0,2x=0,15(x+3) => x=6 => D!
Intern
Intern
avatar
B
Joined: 24 Aug 2015
Posts: 41
Location: Spain
Concentration: General Management, Technology
GMAT 1: 750 Q49 V42
GPA: 3.5
WE: Management Consulting (Consulting)
A chemist has 3 liters of a bleaching chemical, Minum, which is compos  [#permalink]

Show Tags

New post 18 Oct 2015, 08:36
1
(1) The variables in the problem
\(m =\) # liters of minum; \(cm =\)concentration (%) of minum
\(M =\) # liters of Maxim; \(cM =\)concentration (%) of Maxim
\(T =\) # liters in total after mixing both minum and Maxim; \(cT =\)concentration (%) of the mixture

(2) What we know from the stem
From the stem, we know that \(m=3, rm = 5, rM=20\). \(M\) is unknown.
\(T = m + M = 3 + M\)
What we want to know: \(M\)

(3)From all of thi above, we have that

\(\frac{m * cm + M * cM}{T} = cT\)

(4) Plugging in the values from (2):

\(\frac{3 * 5 + M * 20}{(3 + M)} = 15\)

If we solve for \(M\) we get \(M=6\), so is the correct answer.

Hope this helps! Please, kudos!!!
_________________
Please, consider giving kudos if you find my answer helpful in any way :)

Don't worry about the world coming to an end today, it's already tomorrow in Australia
Manager
Manager
User avatar
S
Joined: 21 Jul 2017
Posts: 187
Location: India
Concentration: Social Entrepreneurship, Leadership
GMAT 1: 660 Q47 V34
GPA: 4
WE: Project Management (Education)
Premium Member Reviews Badge
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 16 Aug 2017, 09:45
1
Minum contains 5 percent hydrogen peroxide.
Maxim contains 20 percent hydrogen peroxide.

Minum:Maxim = (20 - 15):(15 - 5) = 1:2. (Using Alligation)

So, since Minum is 3 quarts, Maxim will be 6 quarts!
Senior Manager
Senior Manager
avatar
Joined: 19 Feb 2005
Posts: 410
Location: Milan Italy
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 04 Apr 2005, 12:55
say one quart is 100/3
you have 0.05*100=5
then backsolve
start from C -> 4.5*100/3=150
150*0.2=30
in the new mixture there are 35/250
we needed 37.5 (more)
now D
6*100/3=200
200*0.2=40
45/300
perfect
Manager
Manager
User avatar
Joined: 04 Mar 2005
Posts: 99
Location: NYC
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 05 Apr 2005, 08:12
3
cloaked_vessel wrote:
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrogen peroxide and water. A different type of bleaching chemical, Maxim, which contains 20 percent hydrogen peroxide, will be mixed with the three quarts of Minum. How much of type Maxim should be added to the three quarts of Minum so that the resulting mixture contains 15 percent hydrogen peroxide?

A) 3 quarts

B) 3.75 quarts

C) 4.5 quarts

D) 6 quarts

E) 9 quarts



Ans id 'D'
5% HydPer&Water (HPW) of 3 quart of Minum= .15 q
20% of HPW of x q of Maxim = .2x
Total = .15 + .2x = .15 (3+x)
Solving , x=6 quart
Intern
Intern
avatar
Joined: 25 Jan 2014
Posts: 15
Concentration: Technology, General Management
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 29 Jun 2015, 14:11
cloaked_vessel wrote:
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrogen peroxide and water. A different type of bleaching chemical, Maxim, which contains 20 percent hydrogen peroxide, will be mixed with the three quarts of Minum. How much of type Maxim should be added to the three quarts of Minum so that the resulting mixture contains 15 percent hydrogen peroxide?

A. 3 quarts
B. 3.75 quarts
C. 4.5 quarts
D. 6 quarts
E. 9 quarts


"Bunuel,

can you please explain the solution stepwise as i have no idea as to how to start this sort of mixture questions. Thanks!
Manager
Manager
avatar
Joined: 11 Sep 2013
Posts: 105
Re: A chemist has 3 liters of a bleaching chemical, Minum, which is compos  [#permalink]

Show Tags

New post 18 Oct 2015, 08:30
shyind wrote:
A chemist has 3 liters of a bleaching chemical, Minum, which is composed of 5 percent hydrogen peroxide. A different type of bleaching chemical, Maxim, which is composed of 20 percent hydrogen peroxide, will be mixed with three liters of Minum. How many liters of maxim should be added to the three liters of Minum so that the resulting mixture is 15 percent Hydrogen peroxide.

A. 3

B. 3.75

C. 4.5

D. 6

E. 9


x=the number of liters of Maxim

15(x+3) = 5*3 + 20x
=> x = 6

Ans: D
SVP
SVP
avatar
B
Joined: 06 Nov 2014
Posts: 1877
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 18 Oct 2015, 12:24
We just need to equate the hydrogen peroxide here

5% of 3 + 20% of x = 15% of (x+3)
0.05*3 + 0.2*x = 0.15(3 + x)
0.15 + 0.2x = 0.45 +0.15x
0.05x = 0.3

x = 6 Option D
Intern
Intern
avatar
B
Joined: 03 May 2014
Posts: 3
Location: India
WE: Analyst (Computer Software)
GMAT ToolKit User Reviews Badge
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 04 Apr 2016, 08:41
Minum contains 5% hydrogen peroxide, Maxim contains 20%.
Mixture contains 15%.

Applying ratio and mixture rule Minum and Maxim should be mixed in ratio (20-15):(15-5) or 5:10 or 1:2.

Minum is of 3 quarts. So Maxim should be of 6 quarts.
VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1230
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 26 Jul 2016, 21:00
let x=liters of Maxim to be added
3*.05+x*.2=.15(3+x)
x=6 quarts
Senior SC Moderator
avatar
V
Joined: 22 May 2016
Posts: 3446
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 16 Aug 2017, 18:22
cloaked_vessel wrote:
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrogen peroxide and water. A different type of bleaching chemical, Maxim, which contains 20 percent hydrogen peroxide, will be mixed with the three quarts of Minum. How much of type Maxim should be added to the three quarts of Minum so that the resulting mixture contains 15 percent hydrogen peroxide?

A. 3 quarts
B. 3.75 quarts
C. 4.5 quarts
D. 6 quarts
E. 9 quarts

Simplifying the arithmetic a bit by changing decimal percent concentrations to integers . . .

Let x = amount of Maxim to be added

5(3) + 20(x) = 15(3 + x)
15 + 20x = 45 + 15x
5x = 30
x = 6

Answer D
_________________
SC Butler has resumed! Get two SC questions to practice, whose links you can find by date, here.

If you ask for kudos, be prepared to give them.
Manager
Manager
avatar
B
Joined: 13 Apr 2017
Posts: 76
Location: India
Concentration: General Management, International Business
GMAT 1: 660 Q40 V41
GPA: 3.4
WE: Engineering (Energy and Utilities)
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 21 Aug 2017, 08:34
cloaked_vessel wrote:
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrogen peroxide and water. A different type of bleaching chemical, Maxim, which contains 20 percent hydrogen peroxide, will be mixed with the three quarts of Minum. How much of type Maxim should be added to the three quarts of Minum so that the resulting mixture contains 15 percent hydrogen peroxide?

A. 3 quarts
B. 3.75 quarts
C. 4.5 quarts
D. 6 quarts
E. 9 quarts


Using allegation :
Let x be the quantity of Maxim added
3/x=(20-15)/(15-5)
x=6
Ans. D
Manager
Manager
avatar
B
Joined: 30 Apr 2013
Posts: 76
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 02 Nov 2017, 16:07
how do we backsolve this by using answer options?
Target Test Prep Representative
User avatar
D
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 7777
Location: United States (CA)
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 06 Nov 2017, 18:07
cloaked_vessel wrote:
Three quarts of a bleaching chemical, Minum, contains 5 percent hydrogen peroxide and water. A different type of bleaching chemical, Maxim, which contains 20 percent hydrogen peroxide, will be mixed with the three quarts of Minum. How much of type Maxim should be added to the three quarts of Minum so that the resulting mixture contains 15 percent hydrogen peroxide?

A. 3 quarts
B. 3.75 quarts
C. 4.5 quarts
D. 6 quarts
E. 9 quarts


We can let the number of quarts of Maxim = y and create the following equations:

0.05(3) + 0.2y = 0.15(3 + y)

5(3) + 20y = 15(3 + y)

15 + 20y = 45 + 15y

5y = 30

y = 6

Answer: D
_________________

Scott Woodbury-Stewart

Founder and CEO

Scott@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.

Manager
Manager
avatar
B
Joined: 04 May 2014
Posts: 155
Location: India
WE: Sales (Mutual Funds and Brokerage)
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 14 Nov 2017, 03:12
Weighted avg method.
Formula
w1/w2=(a2-avg)/avg-a1)
a2=20
Avg=15
a1=5
plug in
w1/w2=(20-15)/(10-5)=1/2
w1=3
3/w2=1/2 0r w2=6.
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 12530
Re: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog  [#permalink]

Show Tags

New post 09 Aug 2019, 01:02
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: Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog   [#permalink] 09 Aug 2019, 01:02
Display posts from previous: Sort by

Three quarts of a bleaching chemical, Minum, contains 5 percent hydrog

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





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