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

It is currently 18 Oct 2019, 11:56

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

A solution of X pounds of water and sugar is boiled until 20% of the

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

Hide Tags

Find Similar Topics 
Intern
Intern
avatar
Joined: 20 Apr 2016
Posts: 7
A solution of X pounds of water and sugar is boiled until 20% of the  [#permalink]

Show Tags

New post Updated on: 26 Jul 2016, 23:57
4
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

63% (02:52) correct 37% (03:15) wrong based on 76 sessions

HideShow timer Statistics

A solution of X pounds of water and sugar is boiled until 20% of the water content evaporates. Originally y% of sugar was present in the solution. After evaporation, what percentage of the solution is sugar?

A. 100y/(1-y)
B. 80y/(1-y)
C. 75y/(1-y)
D. 100y/(80-0.2y)
E. 100y/(80+0.2y)

Originally posted by rahulprasad90 on 26 Jul 2016, 19:14.
Last edited by Bunuel on 26 Jul 2016, 23:57, edited 1 time in total.
Renamed the topic, edited the question and added the OA.
EMPOWERgmat Instructor
User avatar
V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15271
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: A solution of X pounds of water and sugar is boiled until 20% of the  [#permalink]

Show Tags

New post 26 Jul 2016, 20:18
Hi rahulprasad90,

You would likely get more of a response if you posted your PS question in the PS Forum here:

gmat-problem-solving-ps-140/

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com
Image


The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 9706
Location: Pune, India
Re: A solution of X pounds of water and sugar is boiled until 20% of the  [#permalink]

Show Tags

New post 26 Jul 2016, 22:02
1
1
rahulprasad90 wrote:
Hello Guys,

Please suggest me an alternative approach to solve this problem.

Q. A solution of X pounds of water and sugar is boiled until 20% of the water content evaporates. Originally y% of sugar was present in the solution. After evaporation, what percentage of the solution is sugar?

a. 100y/(1-y)
b. 80y/(1-y)
c. 75y/(1-y)
d. 100y/80-0.2y
e 100y/80+0.2y

The answer in the guide is (d.)


Assume values when the options have a variable.

Say, x is 100 pounds. Say y% is 50% i.e. the solution had 50 pounds of sugar and 50 pounds of water.
20% water evaporates so 20/100 * 50 = 10 pounds of water evaporates leaving 40 pounds of water.

%age of sugar solution = 50/(50+40) * 100 = 55%

Put y = 50 in the options. Options (A), (B) and (C) make no sense since they will have a negative denominator. Option (E) gives 55% when you put y = 50.

Answer (E)

And yes, please post Problem Solving questions in the the PS forum.
_________________
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 >
Intern
Intern
avatar
Joined: 20 Apr 2016
Posts: 7
Re: A solution of X pounds of water and sugar is boiled until 20% of the  [#permalink]

Show Tags

New post 26 Jul 2016, 23:01
EMPOWERgmatRichC wrote:
Hi rahulprasad90,

You would likely get more of a response if you posted your PS question in the PS Forum here:

gmat-problem-solving-ps-140/

GMAT assassins aren't born, they're made,
Rich



Thanks Rich, I have posted the question.
Intern
Intern
User avatar
Status: Senior GMAT Tutor at examPAL
Joined: 26 Jul 2016
Posts: 1
Re: Please suggest me an alternative approach to solve this question.  [#permalink]

Show Tags

New post 26 Jul 2016, 23:52
rahulprasad90 wrote:
Hello Guys,

Please suggest me an alternative approach to solve this problem.

Q. A solution of X pounds of water and sugar is boiled until 20% of the water content evaporates. Originally y% of sugar was present in the solution. After evaporation, what percentage of the solution is sugar?

a. 100y/(1-y)
b. 80y/(1-y)
c. 75y/(1-y)
d. 100y/80-0.2y
e 100y/80+0.2y

The answer in the guide is (d.)




We'll go for the ALTERNATIVE approach since there are variables in all the answers (which means that any number could work). Since the question deals with percents, the easiest number to use is X = 100. Now let's say that y = 10. Before the evaporation we had 10 pound of sugar and 90 pounds of water. Since only water evaporated, after the evaporation the 10 pounds of sugar remained the same, but the water reduced by 20% of 90 (18 pounds), so we have only 72 pounds of water. 10 out of 82 is the fraction of sugar, so if we multiply it by 100 we get the percents. The correct answer is E: 100y/(80+0.2y) >>> 100x10 / 82
_________________
Jack Oren Jackman
Senior Tutor at examPAL
Current Student
User avatar
Joined: 18 Oct 2014
Posts: 803
Location: United States
GMAT 1: 660 Q49 V31
GPA: 3.98
GMAT ToolKit User
Re: A solution of X pounds of water and sugar is boiled until 20% of the  [#permalink]

Show Tags

New post 27 Jul 2016, 14:07
1
2
rahulprasad90 wrote:
A solution of X pounds of water and sugar is boiled until 20% of the water content evaporates. Originally y% of sugar was present in the solution. After evaporation, what percentage of the solution is sugar?

A. 100y/(1-y)
B. 80y/(1-y)
C. 75y/(1-y)
D. 100y/(80-0.2y)
E. 100y/(80+0.2y)


% of sugar in the new solution = 100 *sugar/ total solution

y% sugar was present means (100-y)% water was present.

In new solution 20% water is evaporated and 80% is remaining. .80(100-y)= 80-.8y

Sugar in the new solution= y
Total solution = y+ 80+.8y= 80+.2y

% of sugar= 100y/(80+.2y)

E is the answer
_________________
I welcome critical analysis of my post!! That will help me reach 700+
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 13259
Re: A solution of X pounds of water and sugar is boiled until 20% of the  [#permalink]

Show Tags

New post 03 Feb 2018, 01:34
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: A solution of X pounds of water and sugar is boiled until 20% of the   [#permalink] 03 Feb 2018, 01:34
Display posts from previous: Sort by

A solution of X pounds of water and sugar is boiled until 20% of the

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





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