Last visit was: 19 Jul 2025, 20:14 It is currently 19 Jul 2025, 20:14
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
User avatar
duahsolo
Joined: 02 Jun 2015
Last visit: 31 Jul 2023
Posts: 144
Own Kudos:
721
 [34]
Given Kudos: 1,196
Location: Ghana
Posts: 144
Kudos: 721
 [34]
3
Kudos
Add Kudos
30
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
duahsolo
Joined: 02 Jun 2015
Last visit: 31 Jul 2023
Posts: 144
Own Kudos:
721
 [6]
Given Kudos: 1,196
Location: Ghana
Posts: 144
Kudos: 721
 [6]
3
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
General Discussion
User avatar
vp101
Joined: 08 Aug 2015
Last visit: 04 May 2024
Posts: 46
Own Kudos:
39
 [2]
Given Kudos: 73
Posts: 46
Kudos: 39
 [2]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
abhimahna
User avatar
Board of Directors
Joined: 18 Jul 2015
Last visit: 06 Jul 2024
Posts: 3,519
Own Kudos:
5,697
 [1]
Given Kudos: 346
Status:Emory Goizueta Alum
Products:
Expert
Expert reply
Posts: 3,519
Kudos: 5,697
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
I also got B for the same reasons. is the OA mentioned correct?
User avatar
Abhishek009
User avatar
Board of Directors
Joined: 11 Jun 2011
Last visit: 18 Jul 2025
Posts: 5,965
Own Kudos:
5,162
 [3]
Given Kudos: 463
Status:QA & VA Forum Moderator
Location: India
GPA: 3.5
WE:Business Development (Commercial Banking)
Posts: 5,965
Kudos: 5,162
 [3]
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
duahsolo
A new beverage, which is a mixture of grape juice and apple juice, is being tested. The test container of 800 milliliters is 15% grape juice. If the response to the beverage causes the maker to increase the percentage of grape juice in the container to 20%, how much grape juice will be added?

A) 30
B) 40
C) 50
D) 120
E) 160

Quote:
The test container of 800 milliliters is 15% grape juice.

Grape Juice = 120 ml
Water = 680 ml
Total Solution = 800 ml

Quote:
If the response to the beverage causes the maker to increase the percentage of grape juice in the container to 20%, how much grape juice will be added

So, \(\frac{(120 + k )}{( 800 + k )}= \frac{20}{100}\)

Or, \(\frac{(120 + k )}{( 800 + k )}= \frac{1}{5}\)

Or, \(600 + 5k = 800 + k\)

Or, \(4k = 200\)

Or, \(k = 50\)

So, 50 ml of Grape juice , must be added , answer must be (C)
User avatar
colorblind
Joined: 30 Dec 2015
Last visit: 23 Jun 2020
Posts: 57
Own Kudos:
Given Kudos: 173
GPA: 3.92
WE:Engineering (Aerospace and Defense)
Posts: 57
Kudos: 142
Kudos
Add Kudos
Bookmarks
Bookmark this Post
VeritasPrepKarishma, Bunuel

Is it possible to do this using weighted avg?
I tried after reading your post on 'weighted avg and mixture problems on GMAT' but cant seem to make it work.
Is weighted avg used only when the same solution is considered and not two separate like in this case?
User avatar
colorblind
Joined: 30 Dec 2015
Last visit: 23 Jun 2020
Posts: 57
Own Kudos:
Given Kudos: 173
GPA: 3.92
WE:Engineering (Aerospace and Defense)
Posts: 57
Kudos: 142
Kudos
Add Kudos
Bookmarks
Bookmark this Post
colorblind
VeritasPrepKarishma, Bunuel

Is it possible to do this using weighted avg?
I tried after reading your post on 'weighted avg and mixture problems on GMAT' but cant seem to make it work.
Is weighted avg used only when the same solution is considered and not two separate like in this case?

VeritasPrepKarishma, Bunuel

Aaahhhhhh I think I got it, please correct me if I am wrong:

Initial grape juice percent = 15% = \(\frac{5}{20}\)
100% concentration grape juice = 1
Grape juice concentration in final mixture = 20% = \(\frac{1}{5}\)

\(\frac{800}{W2} = (1-\frac{1}{5})/(\frac{1}{5} -\frac{5}{20})\)

W2 = 50.
User avatar
KarishmaB
Joined: 16 Oct 2010
Last visit: 19 Jul 2025
Posts: 16,115
Own Kudos:
74,410
 [2]
Given Kudos: 475
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,115
Kudos: 74,410
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
colorblind
colorblind
VeritasPrepKarishma, Bunuel

Is it possible to do this using weighted avg?
I tried after reading your post on 'weighted avg and mixture problems on GMAT' but cant seem to make it work.
Is weighted avg used only when the same solution is considered and not two separate like in this case?

VeritasPrepKarishma, Bunuel

Aaahhhhhh I think I got it, please correct me if I am wrong:

Initial grape juice percent = 15% = \(\frac{5}{20}\)
100% concentration grape juice = 1
Grape juice concentration in final mixture = 20% = \(\frac{1}{5}\)

\(\frac{800}{W2} = (1-\frac{1}{5})/(\frac{1}{5} -\frac{5}{20})\)

W2 = 50.

Yes, correct! Though I would use percentages only. They are easier to manipulate compared with fractions.

800/w2 = (100 - 20)/(20 - 15) = 16/1

w2 = 50
avatar
vrgmat
Joined: 22 Jun 2016
Last visit: 26 Feb 2017
Posts: 4
Own Kudos:
Given Kudos: 4
Posts: 4
Kudos: 2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is it possible to do this using weighted avg?
I tried after reading your post on 'weighted avg and mixture problems on GMAT' but cant seem to make it work.
Is weighted avg used only when the same solution is considered and not two separate like in this case?[/quote]



Aaahhhhhh I think I got it, please correct me if I am wrong:

Initial grape juice percent = 15% = \(\frac{5}{20}\)
100% concentration grape juice = 1
Grape juice concentration in final mixture = 20% = \(\frac{1}{5}\)

\(\frac{800}{W2} = (1-\frac{1}{5})/(\frac{1}{5} -\frac{5}{20})\)

W2 = 50.[/quote]

Yes, correct! Though I would use percentages only. They are easier to manipulate compared with fractions.

800/w2 = (100 - 20)/(20 - 15) = 16/1

w2 = 50[/quote]

Hi VeritasPrepKarishma,

I had tried using the weighted average formula but could not do so. I see that you have performed the following:

Comparing the step 800/w2 = (100 - 20)/(20 - 15) = 16/1 to the weighted average formula, i don't seem to figure why we have taken 100 % here.

n1/n2=(A2-Aw)/(Aw-A1). So Aw here is 20, A1 is 15, n1 is 800. How did you take A2 as 100? What is the logic behind it? Can you please explain it to me?
User avatar
colorblind
Joined: 30 Dec 2015
Last visit: 23 Jun 2020
Posts: 57
Own Kudos:
Given Kudos: 173
GPA: 3.92
WE:Engineering (Aerospace and Defense)
Posts: 57
Kudos: 142
Kudos
Add Kudos
Bookmarks
Bookmark this Post
vrgmat
Is it possible to do this using weighted avg?
I tried after reading your post on 'weighted avg and mixture problems on GMAT' but cant seem to make it work.
Is weighted avg used only when the same solution is considered and not two separate like in this case?



Aaahhhhhh I think I got it, please correct me if I am wrong:

Initial grape juice percent = 15% = \(\frac{5}{20}\)
100% concentration grape juice = 1
Grape juice concentration in final mixture = 20% = \(\frac{1}{5}\)

\(\frac{800}{W2} = (1-\frac{1}{5})/(\frac{1}{5} -\frac{5}{20})\)

W2 = 50.[/quote]

Yes, correct! Though I would use percentages only. They are easier to manipulate compared with fractions.

800/w2 = (100 - 20)/(20 - 15) = 16/1

w2 = 50[/quote]

Hi VeritasPrepKarishma,

I had tried using the weighted average formula but could not do so. I see that you have performed the following:

Comparing the step 800/w2 = (100 - 20)/(20 - 15) = 16/1 to the weighted average formula, i don't seem to figure why we have taken 100 % here.

n1/n2=(A2-Aw)/(Aw-A1). So Aw here is 20, A1 is 15, n1 is 800. How did you take A2 as 100? What is the logic behind it? Can you please explain it to me?[/quote]

Initial concentration of grape juice is 15% and we are asked to increase the percentage of grape juice to 20%. The only way to do this is by adding a certain amount of 100% grape juice and that is where the 100% comes from.
avatar
vrgmat
Joined: 22 Jun 2016
Last visit: 26 Feb 2017
Posts: 4
Own Kudos:
Given Kudos: 4
Posts: 4
Kudos: 2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
colorblind
vrgmat
Is it possible to do this using weighted avg?
I tried after reading your post on 'weighted avg and mixture problems on GMAT' but cant seem to make it work.
Is weighted avg used only when the same solution is considered and not two separate like in this case?



Aaahhhhhh I think I got it, please correct me if I am wrong:

Initial grape juice percent = 15% = \(\frac{5}{20}\)
100% concentration grape juice = 1
Grape juice concentration in final mixture = 20% = \(\frac{1}{5}\)

\(\frac{800}{W2} = (1-\frac{1}{5})/(\frac{1}{5} -\frac{5}{20})\)

W2 = 50.

Yes, correct! Though I would use percentages only. They are easier to manipulate compared with fractions.

800/w2 = (100 - 20)/(20 - 15) = 16/1

w2 = 50[/quote]

Hi VeritasPrepKarishma,

I had tried using the weighted average formula but could not do so. I see that you have performed the following:

Comparing the step 800/w2 = (100 - 20)/(20 - 15) = 16/1 to the weighted average formula, i don't seem to figure why we have taken 100 % here.

n1/n2=(A2-Aw)/(Aw-A1). So Aw here is 20, A1 is 15, n1 is 800. How did you take A2 as 100? What is the logic behind it? Can you please explain it to me?[/quote]

Initial concentration of grape juice is 15% and we are asked to increase the percentage of grape juice to 20%. The only way to do this is by adding a certain amount of 100% grape juice and that is where the 100% comes from.[/quote]

Got it. Thank you very much colorblind :)
avatar
rt9
Joined: 08 Jul 2013
Last visit: 17 Sep 2020
Posts: 9
Own Kudos:
25
 [2]
Given Kudos: 38
Posts: 9
Kudos: 25
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
this is poorly worded. if the test container is of 800ml, why should i assume that it can hold 850ml??
avatar
KM2018AA
Joined: 11 Sep 2016
Last visit: 08 Feb 2021
Posts: 63
Own Kudos:
Given Kudos: 23
Location: India
Concentration: General Management, Leadership
GMAT 1: 710 Q47 V40
GPA: 3
WE:Sales (Manufacturing)
Products:
GMAT 1: 710 Q47 V40
Posts: 63
Kudos: 21
Kudos
Add Kudos
Bookmarks
Bookmark this Post
rt9
this is poorly worded. if the test container is of 800ml, why should i assume that it can hold 850ml??

The exact same assumption stumped me too.
I interpreted the container to be of 800 ml Volume.
Now to me, "response", meant that someone would suck out some volume of liquid from the 800 ml filled container resulting in reduction of the liquid
Now one has to add some X ml of Grape juice to make it back to 800 ml mixture
Hence I computed (120 + X)/800= 0.2 resulting in X= 40


May be I interpreted it very incorrectly

:)
KM
User avatar
quantumliner
Joined: 24 Apr 2016
Last visit: 26 Sep 2018
Posts: 244
Own Kudos:
753
 [3]
Given Kudos: 48
Posts: 244
Kudos: 753
 [3]
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
In the original Test Container of 800 milliliters, grape juice is 15%, i.e. 120 milliliters

To make the grape juice % to 20%, let the amount of grape juice added = x milliliters

(120+x)/(800+x) = 0.2

Solving for X gives as x = 50

Answer is C. 50
User avatar
rohit8865
Joined: 05 Mar 2015
Last visit: 18 Jul 2025
Posts: 817
Own Kudos:
954
 [1]
Given Kudos: 45
Products:
Posts: 817
Kudos: 954
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
A new beverage, which is a mixture of grape juice and apple juice, is being tested. The test container of 800 milliliters is 15% grape juice. If the response to the beverage causes the maker to increase the percentage of grape juice in the container to 20%, how much grape juice will be added?

A. 30
B. 40
C. 50
D. 120
E. 160


Initial volume of grape juice in beverage 15% of 800 = 120ML
let X amount be added then
this new volume will represent 20% of final volume
120+x = 20% of (800+x)
solving X =50 ML

Ans C
User avatar
KrishnakumarKA1
Joined: 05 Jan 2017
Last visit: 13 Oct 2020
Posts: 403
Own Kudos:
Given Kudos: 15
Location: India
Posts: 403
Kudos: 302
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
A new beverage, which is a mixture of grape juice and apple juice, is being tested. The test container of 800 milliliters is 15% grape juice. If the response to the beverage causes the maker to increase the percentage of grape juice in the container to 20%, how much grape juice will be added?

A. 30
B. 40
C. 50
D. 120
E. 160
let the grape juice added be x
apple juice in initial mixture = 0.85*800
apple juice in final mixture = 0.8(800 +x)
since the apple juice in both the mixture is same, therefore
0.85*800 = 0.8(800+ x)
0.05*800 = 0.8x
or x= 0.05*800/0.8 = 50ml

Option C
User avatar
jkolachi
Joined: 12 Oct 2015
Last visit: 05 Feb 2025
Posts: 237
Own Kudos:
390
 [2]
Given Kudos: 144
Location: Canada
Concentration: Leadership, Accounting
GMAT 1: 700 Q47 V39
GPA: 3
WE:Accounting (Accounting)
Products:
GMAT 1: 700 Q47 V39
Posts: 237
Kudos: 390
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
A new beverage, which is a mixture of grape juice and apple juice, is being tested. The test container of 800 milliliters is 15% grape juice. If the response to the beverage causes the maker to increase the percentage of grape juice in the container to 20%, how much grape juice will be added?

A. 30
B. 40
C. 50
D. 120
E. 160

800 ml, 15% grape juice = 120ml grape & 85% apple = 680.

Now 680 must be 80% of new mixture so find value that 680ml is 80% of. so (680/8)*10 = 850 hence 50 more.
User avatar
JeffTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 04 Mar 2011
Last visit: 05 Jan 2024
Posts: 2,996
Own Kudos:
Given Kudos: 1,646
Status:Head GMAT Instructor
Affiliations: Target Test Prep
Expert
Expert reply
Posts: 2,996
Kudos: 7,952
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
A new beverage, which is a mixture of grape juice and apple juice, is being tested. The test container of 800 milliliters is 15% grape juice. If the response to the beverage causes the maker to increase the percentage of grape juice in the container to 20%, how much grape juice will be added?

A. 30
B. 40
C. 50
D. 120
E. 160

Initially there is 800 x 0.15 = 120 ml of grape juice and thus 680 ml of apples juice. We can let g = the amount of grape juice to be added and create the equation:

(120 + g)/(800 + g) = 1/5

5(120 + g) = 800 + g

600 + 5g = 800 + g

4g = 200

g = 50

Alternate Solution:

To 800 ml of 15% grape juice, we add x ml of 100% grape juice to obtain (800 + x) ml of 20% grape juice. Converting the percentages to decimals, we can create the equation:

800(0.15) + x(1.0) = (800 + x)(0.20)

120 + x = 160 + 0.20x

0.8x = 40

8x = 400

x = 50

Answer: C
User avatar
LordStark
User avatar
Current Student
Joined: 31 Aug 2016
Last visit: 28 Feb 2023
Posts: 295
Own Kudos:
Given Kudos: 911
Status:Valar Dohaeris
GMAT 1: 700 Q49 V37
Products:
GMAT 1: 700 Q49 V37
Posts: 295
Kudos: 1,069
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
A new beverage, which is a mixture of grape juice and apple juice, is being tested. The test container of 800 milliliters is 15% grape juice. If the response to the beverage causes the maker to increase the percentage of grape juice in the container to 20%, how much grape juice will be added?

A. 30
B. 40
C. 50
D. 120
E. 160



let x ml of grape juice(100 % grapes juice mixture) is required to be added to make the final % of grape juice to be 20 %

therefore
800/x = (100 - 20)/(20-15)

x = 800/16 = 50 %
avatar
fireagablast
Joined: 30 Jun 2019
Last visit: 17 Aug 2021
Posts: 265
Own Kudos:
Given Kudos: 8
Posts: 265
Kudos: 120
Kudos
Add Kudos
Bookmarks
Bookmark this Post
800*15/100 = 120 currently in mixture

new mixture
(800+x)*20/100 = 120 + x; new mixture at 20% is equal to the new total amount of grape juice
(800+x)/5 = 120 + x
800+x = 600 + 5x
200 = 4x
x = 50
 1   2   
Moderators:
Math Expert
102627 posts
PS Forum Moderator
698 posts