Mixture of milk

Expert replies

rohit_gmat: Master | Next Rank: 500 Posts; Posts: 158; Joined: Wed Jun 16, 2010 8:21 amFollowed by: 1 member; Thanked: 13 times

by rohit_gmat » Thu Oct 20, 2011 9:32 am

Three grades of milk: 1%, 2%, and 3% fat by volume. x gallons of 1%, y gallons of 2%, and z gallons of 3% are mixed to give x + y + z gallons of 1.5%. What is x in terms of y and z?
a. y + 3z
b. (y + z)/4
c. 2y + 3z
d. 3y + z
e. 3y + 4z

totally lost

plz help.
can this solved by plugging in numbers? how do we pick numbers for this one?

Like this post

Source: Beat The GMAT — Problem Solving | Thu Oct 20, 2011 9:32 am

GMAT/MBA Expert

Anurag@Gurome: GMAT Instructor; Posts: 3835; Joined: Fri Apr 02, 2010 10:00 pmFollowed by: 523 members; Location: Milpitas, CA; Thanked: 1854 times; GMAT Score:770

by Anurag@Gurome » Thu Oct 20, 2011 9:36 am

rohit_gmat wrote:Three grades of milk: 1%, 2%, and 3% fat by volume. x gallons of 1%, y gallons of 2%, and z gallons of 3% are mixed to give x + y + z gallons of 1.5%. What is x in terms of y and z?

Form the question we can write the following equation,
--> 1*x + 2*y + 3*z = 1.5*(x + y + z)
--> x + 2y + 3z = 1.5x + 1.5y + 1.5z
--> 0.5x = 0.5y + 1.5z
--> x = y + 3z

The correct answer is A.

Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/

Like this post

rohit_gmat: Master | Next Rank: 500 Posts; Posts: 158; Joined: Wed Jun 16, 2010 8:21 amFollowed by: 1 member; Thanked: 13 times

by rohit_gmat » Thu Oct 20, 2011 9:51 am

thanks !! the algebraic way looks much clearer...!!!
is there any way to solve this with plugging in numbers?

Like this post

shankar.ashwin: Legendary Member; Posts: 966; Joined: Sat Jan 02, 2010 8:06 amFollowed by: 21 members; Thanked: 230 times

by shankar.ashwin » Thu Oct 20, 2011 10:21 am

You could substitute numbers as well. Notice the resultant is between 1 and 2. So mixing an equal amount of 1% and 2% milk would yield an 1.5% milk.

Hence substitute
X=1
Y=1
Z=0.

You can see X=Y here and Z is 0.

From the answer choices you can see only A satisfies this. X=Y+3Z -> X=Y + 3(0)

Like this post

neelgandham: Community Manager; Posts: 1060; Joined: Fri May 13, 2011 6:46 amFollowed by: 52 members; Location: Utrecht, The Netherlands; Thanked: 318 times

by neelgandham » Thu Oct 20, 2011 1:06 pm

GMAT Prep question isn't it ?

(1/100)*x + (2/100)*y + (3/100)*z = (1.5/100)*(x+y+z)

=> x = y + 3z

@Anurag - Is there another way(other than algebra/substitution) of solving this? like say using ratios ?

Anil Gandham
Welcome to BEATtheGMAT | Photography | Getting Started | BTG Community rules | MBA Watch
Check out GMAT Prep Now's online course at https://www.gmatprepnow.com/

Like this post

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Thu Oct 20, 2011 7:57 pm

I posted a non-algebraic solution here:

https://www.beatthegmat.com/mixturess-t91444.html

Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Like this post

neelgandham: Community Manager; Posts: 1060; Joined: Fri May 13, 2011 6:46 amFollowed by: 52 members; Location: Utrecht, The Netherlands; Thanked: 318 times

by neelgandham » Fri Oct 21, 2011 2:21 am

GMATGuruNY wrote:I posted a non-algebraic solution here:

https://www.beatthegmat.com/mixturess-t91444.html

Thanks GMATGuru - Is there another way(other than algebra/substitution) of solving this? like say using ratios ? The solution provided by you is more of a substitution method, isn't it?

Anil Gandham
Welcome to BEATtheGMAT | Photography | Getting Started | BTG Community rules | MBA Watch
Check out GMAT Prep Now's online course at https://www.gmatprepnow.com/

Like this post

GMATGuruNY: GMAT Instructor; Posts: 15539; Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members; Location: New York, NY; Thanked: 13060 times; GMAT Score:790

by GMATGuruNY » Fri Oct 21, 2011 5:18 am

neelgandham wrote:
GMATGuruNY wrote:I posted a non-algebraic solution here:

https://www.beatthegmat.com/mixturess-t91444.html
Thanks GMATGuru - Is there another way(other than algebra/substitution) of solving this? like say using ratios ? The solution provided by you is more of a substitution method, isn't it?

More than one ratio will yield the desired mixture. Check my post at the bottom of the following thread:

https://www.beatthegmat.com/allegation-t69552.html

To solve a mixture problem with 3 ingredients, I would use algebra or plug in numbers.

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review