Last visit was: 19 Jul 2025, 14:26 It is currently 19 Jul 2025, 14:26
Home
GMAT
Messages
Tests
Schools
Events
Rewards
Chat
My Profile
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 19 July 2025
Posts: 102,625
Own Kudos:
742,778
 [14]
Given Kudos: 98,235
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 102,625
Kudos: 742,778
 [14]
A milkman mixed 4 litres of water with 10 litres of milk. He boiled on 11 Mar 2021, 08:30
Kudos
Add Kudos
14
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

55% (hard)

Question Stats:

74% (02:51) correct 26% (03:05) wrong based on 156 sessions

History

Date
Time
Result
Not Attempted Yet
A milkman mixed 4 litres of water with 10 litres of milk. He boiled one fourth of this mixture till the water content in it, halved. Then he added it to remaining mixture. What is the proportion of milk in the mixture after the process?

A. 7/10

B. 20/27

C. 21/27

D. 18/15

E. 19/15
ShowHide Answer
Official Answer
B
User avatar
EgmatQuantExpert
User avatar
e-GMAT Representative
Joined: 04 Jan 2015
Last visit: 02 Apr 2024
Posts: 3,681
Own Kudos:
19,481
 [2]
Given Kudos: 165
Expert
Expert reply
Posts: 3,681
Kudos: 19,481
 [2]
A milkman mixed 4 litres of water with 10 litres of milk. He boiled on 30 Mar 2021, 07:43
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Given:
    • A milkman mixed 4 liters of water with 10 liters of milk.
    • He boiled one-fourth of this mixture till the water content in it halved.
      o Then he added it to the remaining mixture.

To find:
    • The proportion of milk in the mixture after the process.

Approach and Working out:

The volume of solution after mixing 4 liters of water with 10 liters of milk =14L

¾ of the solution that is kept as it is:
    • Volume of solution that was not taken out = 14 - 3.5 = 10.5L.
      o Milk and water in solution is in the ratio of 10:4 = 5:2
    • Hence, quantity of milk in ¾ of the solution = \(\frac{5}{7} \)× 10.5 =7.5L
      o Quantity of water in ¾ of the solution = \(\frac{2}{7}\) × 10.5 =3 L

¼ of this solution that is taken out.
    • Volume of solution taken out = 14/4 = 3.5 L.
      o Milk and water in 3.5L solution is in the ratio of 10:4 = 5:2
    • Hence, quantity of milk in ¼ of the solution = \(\frac{5}{7} \) × 3.5 =2.5L
      o Quantity of water in ¼ of the solution = \(\frac{2}{7}\) × 3.5 =1 L

This 3.5L of the mixture is boiled until the water quantity becomes half.
    • New quantity of milk = Old quantity of milk = 2.5 L
    • New quantity of water = ½ of 1 L = 0.5L

Now, this mixture is added to the original solution again.
    • Total quantity of milk = 7.5 + 2.5 = 10L
    • Total quantity of water = 3+0.5 = 3.5L

The proportion of milk after the process = \(\frac{10}{13.5}\) =20/27
Hence, option B is the correct answer.

Correct Answer: Option B
User avatar
TestPrepUnlimited
User avatar
Joined: 17 Sep 2014
Last visit: 30 Jun 2022
Posts: 1,226
Own Kudos:
1,067
Given Kudos: 6
Location: United States
GMAT 1: 780 Q51 V45
GRE 1: Q170 V167
Expert
Expert reply
GMAT 1: 780 Q51 V45
GRE 1: Q170 V167
Posts: 1,226
Kudos: 1,067
A milkman mixed 4 litres of water with 10 litres of milk. He boiled on 30 Mar 2021, 12:57
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
A milkman mixed 4 litres of water with 10 litres of milk. He boiled one fourth of this mixture till the water content in it, halved. Then he added it to remaining mixture. What is the proportion of milk in the mixture after the process?

A. 7/10

B. 20/27

C. 21/27

D. 18/15

E. 19/15

One-fourth of the content: 1 L of water and 2.5 L of milk.

After boiling: 0.5 L of water and 2.5 L of milk.

So we can see from this boiling process, all that happened was 0.5 L of water was boiled and milk did not change.

Then we are left with 3.5 L water and 10 L milk. The proportion of milk is \(\frac{10}{13.5} = \frac{20}{27}\)

Ans: B
avatar
astiles67
avatar
Joined: 02 Mar 2020
Last visit: 13 Feb 2022
Posts: 18
Own Kudos:
9
 [1]
Given Kudos: 2
Posts: 18
Kudos: 9
 [1]
A milkman mixed 4 litres of water with 10 litres of milk. He boiled on 09 Apr 2021, 20:23
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
A milkman mixed 4 litres of water with 10 litres of milk. He boiled one fourth of this mixture till the water content in it, halved. Then he added it to remaining mixture. What is the proportion of milk in the mixture after the process?

A. 7/10

B. 20/27

C. 21/27

D. 18/15

E. 19/15

There are 2 grammatical problems with this question that can lead to wrong answers.

"He boiled one fourth of this mixture till the water content in it, halved."

1. We do not know if this means that he took 1/4 OUT of the prior mixture or if is is an additional mixture that would be 1/4 of the prior mixture.

2. Water and milk can boil. It is ambiguous as to whether the water AND milk boil in half, or if just the water boils in half while the milk stays the same.

I do understand why GMAT questions intentionally make ambiguous directions.
avatar
argerniki
avatar
Joined: 12 May 2020
Last visit: 09 Aug 2021
Posts: 53
Own Kudos:
20
Given Kudos: 230
GPA: 4
Products:
My Reviews
Posts: 53
Kudos: 20
A milkman mixed 4 litres of water with 10 litres of milk. He boiled on 12 Apr 2021, 03:49
Kudos
Add Kudos
Bookmarks
Bookmark this Post
astiles67
Bunuel
A milkman mixed 4 litres of water with 10 litres of milk. He boiled one fourth of this mixture till the water content in it, halved. Then he added it to remaining mixture. What is the proportion of milk in the mixture after the process?

A. 7/10

B. 20/27

C. 21/27

D. 18/15

E. 19/15

There are 2 grammatical problems with this question that can lead to wrong answers.

"He boiled one fourth of this mixture till the water content in it, halved."

1. We do not know if this means that he took 1/4 OUT of the prior mixture or if is is an additional mixture that would be 1/4 of the prior mixture.

2. Water and milk can boil. It is ambiguous as to whether the water AND milk boil in half, or if just the water boils in half while the milk stays the same.

I do understand why GMAT questions intentionally make ambiguous directions.

+1

While I think that the 1st point is clear ("He boiled one fourth of this mixture till the water content in it, halved."), I made the same mistake and halved the proportion of milk in the part that was boiled down as well.
An additional explanation ("Note: milk has a higher boiling point than water") would clear up the ambiguity.
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,449
Own Kudos:
1,013
Posts: 37,449
Kudos: 1,013
A milkman mixed 4 litres of water with 10 litres of milk. He boiled on 18 Jun 2025, 09:37
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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.
Moderators:
Bunuel
Math Expert
102625 posts
Krunaal
PS Forum Moderator
698 posts