GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 05 Aug 2020, 06:18

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

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

A feed store sells two varieties of birdseed: Brand A, which

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

Hide Tags

Intern
Joined: 16 Jun 2008
Posts: 5
A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

17 Dec 2009, 14:48
2
56
00:00

Difficulty:

35% (medium)

Question Stats:

73% (01:43) correct 27% (02:09) wrong based on 1187 sessions

HideShow timer Statistics

A feed store sells two varieties of birdseed: Brand A, which is 40% millet and 60% sunflower, and Brand B, which is 65% millet and 35% safflower. If a customer purchases a mix of the two types of birdseed that is 50% millet, what percent of the mix is Brand A?

A) 40%

B) 45%

C) 50 %

D) 60 %

E) 55 %
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10785
Location: Pune, India
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

02 Jun 2014, 19:47
10
13
umaa wrote:
A feed store sells two varieties of birdseed: Brand A, which is 40% millet and 60% sunflower, and Brand B, which is 65% millet and 35% safflower. If a customer purchases a mix of the two types of birdseed that is 50% millet, what percent of the mix is Brand A?

A) 40%

B) 45%

C) 50 %

D) 60 %

E) 55 %

Use the scale method:
40% millet and 65% millet are mixed together to get 50% millet.

w1/w2 = (65 - 50)/(50 - 40) = 15/10 = 3/2
So brand A is 3/5 i.e. 60% of the mix.

For more on this method, check: http://www.veritasprep.com/blog/2011/03 ... -averages/
_________________
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
Joined: 13 Dec 2013
Posts: 33
GMAT 1: 620 Q42 V33
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

02 Jun 2014, 17:43
14
8
Took me 1min.

Only take the Millet percentages since that's the goal mix you´re trying to find.

0.40x + 0.65(1-x) = 0.50
0.40x+ 0.65 - 0.65x = 0.50
0.25x = 0.15
x = 0.60

Hope it helps!
General Discussion
Manager
Joined: 09 May 2009
Posts: 139
Re: Percent Mix Problem  [#permalink]

Show Tags

17 Dec 2009, 19:58
7
3
this can be done easily with the tricks of mix and alligation

ans is 60%

40________________________65
____________50____________
65-50=15______:_______ 50-40=10

so ratio is 15:10
% is 15/25 *100=60
Intern
Joined: 14 May 2014
Posts: 39
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

19 May 2014, 21:17
6
7
Another method to solve this question using equations:

1 kg of Brand A will have 400g millet and 600g sunflower.
1 kg of Brand B will gave 650g millet and 350g sunflower.

Suppose,x kg of Brand A and y kg of Brand B are in the mixture.
Then total weight of millet = 400x+650y g
Total weight of mixture = 1000x + 1000y g
Given that millet is 500% hence
(400x+650y)/(1000x + 1000y) = 1/2
or, 800x + 1300y = 1000x+1000y
or 300y=200x
or, x/y = 3/2
% of Brand A = (3/(3+2))*100 =60%
Hence answer is D
Intern
Joined: 17 Dec 2009
Posts: 16
Re: Percent Mix Problem  [#permalink]

Show Tags

17 Dec 2009, 15:21
2
Another alligation method:

Set up a table:
Millet Sunflower
Brand A 40% 60%
Brand B 65% 35%

B--------Average--------A
(from mean) (from mean)
15 50 10

So A/A+B = 15/25 = 60%
Manager
Status: I am not a product of my circumstances. I am a product of my decisions
Joined: 20 Jan 2013
Posts: 102
Location: India
Concentration: Operations, General Management
GPA: 3.92
WE: Operations (Energy and Utilities)
A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

23 Oct 2014, 05:52
2
Blackbox wrote:
Bumping up and asking for a different explanation. So, according to MGMAT's explanation, they used a table method to solve this question - which is not very helpful. Could someone explain in a simpler way to solve this using the table method? Also, isn't there "one ring to rule them all" for this type of questions?

p.s.: Sadly,I can't attach a screen grab of their explanation to this reply

A feed store sells two varieties of birdseed: Brand A, which is 40% millet and 60% sunflower, and Brand B, which is 65% millet and 35% safflower. If a customer purchases a mix of the two types of birdseed that is 50% millet, what percent of the mix is Brand A?

A) 40%

B) 45%

C) 50 %

D) 60 %

E) 55 %

Yes there is a simple method :

Consider the following method

Brand A : 40% millet and 60% sunflower
Brand B : 65% millet and 35% safflower

Mix : 50% millet

Here the weighted average is 50%,

Now Brand A has 40% millet, which is 10% less than the weighted average of mix = - 0.10 A --------------- I
Similarly, Brand B has 65 % millet, which is 15 % more than the weighted average of mix = + 0.15 B ------------ II

Now, both Brand A and Brand B are combined to give a 50% mix containing millet, so equate I and II

implies, 0.10 A = 0.15 B

Therefore A/B = 0.15/0.10 = 3/2

A : B : (A + B) = 3 : 2 : (3+2) = 3 : 2 : 5

We have to find, percent of the mix is Brand A i.e. A : (A + B) = 3 : 5 = (3 / 5) * 100 = 60 %

Here is a pictorial representation :

Brand A= 40%------------------------10% or 0.10 below average, A times-----------------Total below = - 0.10 A

---------------------------------------------------------------------------------------- Average = 50% or 0.50

Brand B = 65 %--------------------------15% or 0.15 above average, B times-----------------Total above = + 0.15 B

Since the amount below the average has to equal the average above the average; therefore,
0.10 A = 0.15 B

A/B = 3/2

A:B: Total = 3:2:5

Therefore
A/Total = 3:5 = 60 %
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 17276
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

20 Apr 2015, 17:58
2
Hi JeroenReunis,

Your calculations are correct; you make a mistake in your end deduction though.

When you get to this calculation....

.15Y = .1X

You have a RATIO of X to Y. Here's what you need to do with this ratio to get to the correct answer:

Let's multiply both sides by 100 to get rid of the decimal....

15Y = 10X

From here, you can do work in a couple of different ways. I'm going to continue to do "ratio math"....

15Y = 10X

15/10 = X/Y

3/2 = X/Y

This means that for every 3 "units" of X, we have 2 "units" of Y. So, for every 5 total units, 3/5 are X and 2/5 are Y. The question asks for the percent of the mixture that is X...

3/5 = 60%

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

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Intern
Joined: 19 Mar 2014
Posts: 7
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

01 Jul 2014, 07:55
1
why r we taking 15/10 and not 10/15 when 10 denotes brand A part .?
Manager
Status: I am not a product of my circumstances. I am a product of my decisions
Joined: 20 Jan 2013
Posts: 102
Location: India
Concentration: Operations, General Management
GPA: 3.92
WE: Operations (Energy and Utilities)
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

23 Oct 2014, 20:08
1
Blackbox wrote:
Thanks for the explanation, Ashish.

1. Does this approach work with all sorts of problems with percents?
2. How did you come up with 50% as a weighted average? Is it because it is given "If a customer purchases a mix of the two types of birdseed that is 50% millet"?

This approach works for mixture problems.

Its better to convert the information into ratios. It causes less confusion. This is a weighted avg problem of sorts, because you got 2 Brands and the final mix contains some part of Brand and some part of Brand B. This is evident from the fact that

Brand A has 40 % millet, Brand B has 65 % millet and Mix has 50 % millet

40% Millet in Brand A------------ 50% Millet in Mix ------------ 65% Millet in Brand B.

As you see, Brand A and Brand B combine to form the Mix. Had the Quantity of Brand A and Quantity of Brand B been Equal then the Mix would have had 52.5% Millet. But this is not the case here. We are given that the Mix has 50% millet i.e. the Quantity of Brand A in mix is greater than Quantity of Brand B in mix since 50% is closer to 40% than it is to 65%. So, this situation can only arise if and only if this was a weighted average problem.

In case you need the Weighted Avg formula,

Weighted Avg = [(Quantity of A*Quality of A) + (Quantity of B*Quality of B)] / ( Quantity of A + Quantity of B )
Manager
Joined: 30 May 2012
Posts: 194
Location: United States (TX)
Concentration: Finance, Marketing
GPA: 3.3
WE: Information Technology (Consulting)
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

26 Oct 2014, 05:39
1
hsbinfy wrote:
hey guys , m satisified with the above explanations but let me give u an easy one which is undersble by a newbie.

this is very a simple approach u can also find same question in og13(i guess in the last questions)

consider brand A-40(millet) and 60(other one)

n brand B -0.65x(millet) and 0.35x(other one)

acc to question the eq is

40+ 0.65x=0.5(x+100)

u get x=200/3

now percentage =brand A/mixture

100/(200/3) +100 =3/5 which is 60%

simple D

-h

Yup. That's one other explanation I read on MGMAT. Thanks for bringing it up, HSBINFY.
Senior Manager
Joined: 07 Aug 2011
Posts: 488
Concentration: International Business, Technology
GMAT 1: 630 Q49 V27
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

21 Apr 2015, 02:29
1
umaa wrote:
A feed store sells two varieties of birdseed: Brand A, which is 40% millet and 60% sunflower, and Brand B, which is 65% millet and 35% safflower. If a customer purchases a mix of the two types of birdseed that is 50% millet, what percent of the mix is Brand A?

A) 40%

B) 45%

C) 50 %

D) 60 %

E) 55 %

Attachments

gmatclub.jpg [ 80.08 KiB | Viewed 15581 times ]

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 17276
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

21 Apr 2015, 17:48
1
Hi JeroenReunis,

The given equation can be re-written as a ratio, but your interpretation of it is not correct....

10X = 15Y

means "10 times X" equals "15 times Y"

This does NOT mean "for every 10X there are 15Y"

You can prove this by TESTing VALUES.

10X = 15Y

IF....
X = 3 then Y = 2

THIS is the ratio that actually exists: X:Y = 3 to 2

Any additional sets of values that you plug in for X and Y will confirm this ratio.

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

The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 10785
Location: Pune, India
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

02 Jul 2014, 21:31
kunaljain1701 wrote:
why r we taking 15/10 and not 10/15 when 10 denotes brand A part .?

It's actually 15 parts of brand A and 10 parts of brand B. So fraction of brand A is 15/25. The w1 and w2 in the formula are the weights of brand A and brand B. They do not represent the fraction of total but only the parts of brand A and brand B. Check out the link I have given above. It discusses weights in more detail.
_________________
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 >
Manager
Joined: 30 May 2012
Posts: 194
Location: United States (TX)
Concentration: Finance, Marketing
GPA: 3.3
WE: Information Technology (Consulting)
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

23 Oct 2014, 03:55
Bumping up and asking for a different explanation. So, according to MGMAT's explanation, they used a table method to solve this question - which is not very helpful. Could someone explain in a simpler way to solve this using the table method? Also, isn't there "one ring to rule them all" for this type of questions?

p.s.: Sadly,I can't attach a screen grab of their explanation to this reply
Manager
Joined: 30 May 2012
Posts: 194
Location: United States (TX)
Concentration: Finance, Marketing
GPA: 3.3
WE: Information Technology (Consulting)
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

23 Oct 2014, 09:26
Thanks for the explanation, Ashish.

1. Does this approach work with all sorts of problems with percents?
2. How did you come up with 50% as a weighted average? Is it because it is given "If a customer purchases a mix of the two types of birdseed that is 50% millet"?
Manager
Status: I am not a product of my circumstances. I am a product of my decisions
Joined: 20 Jan 2013
Posts: 102
Location: India
Concentration: Operations, General Management
GPA: 3.92
WE: Operations (Energy and Utilities)
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

23 Oct 2014, 20:11
Ashishmathew01081987 wrote:
Blackbox wrote:
Thanks for the explanation, Ashish.

1. Does this approach work with all sorts of problems with percents?
2. How did you come up with 50% as a weighted average? Is it because it is given "If a customer purchases a mix of the two types of birdseed that is 50% millet"?

This approach works for mixture problems.

Its better to convert the information into ratios. It causes less confusion. This is a weighted avg problem of sorts, because you got 2 Brands and the final mix contains some part of Brand and some part of Brand B. This is evident from the fact that

Brand A has 40 % millet, Brand B has 65 % millet and Mix has 50 % millet

40% Millet in Brand A------------ 50% Millet in Mix ------------ 65% Millet in Brand B.

As you see, Brand A and Brand B combine to form the Mix. Had the Quantity of Brand A and Quantity of Brand B been Equal then the Mix would have had 52.5% Millet. But this is not the case here. We are given that the Mix has 50% millet i.e. the Quantity of Brand A in mix is greater than Quantity of Brand B in mix since 50% is closer to 40% than it is to 65%. So, this situation can only arise if and only if this was a weighted average problem.

In case you need the Weighted Avg formula,

Weighted Avg = [(Quantity of A*Quality of A) + (Quantity of B*Quality of B)] / ( Quantity of A + Quantity of B )

Also, keep an eye on the value that is changing. Here, the value is that of the proportion of Millet. Sunflower and safflower values are of no use.
Senior Manager
Joined: 02 Mar 2012
Posts: 257
Schools: Schulich '16
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

24 Oct 2014, 23:24
hey guys , m satisified with the above explanations but let me give u an easy one which is undersble by a newbie.

this is very a simple approach u can also find same question in og13(i guess in the last questions)

consider brand A-40(millet) and 60(other one)

n brand B -0.65x(millet) and 0.35x(other one)

acc to question the eq is

40+ 0.65x=0.5(x+100)

u get x=200/3

now percentage =brand A/mixture

100/(200/3) +100 =3/5 which is 60%

simple D

-h
Intern
Joined: 29 Jan 2015
Posts: 8
Concentration: Finance, Economics
GPA: 3.7
Re: A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

20 Apr 2015, 10:14
Could anyone explain why this solution is incorrect;

0.4x+0.65y=0.5(x+y)
0.15y=0.1x -> Total weight is 0.25
x= 40% of total.

For reference in this problem this approach works.

Seed mixture X is 40 percent ryegrass and 60 percent bluegrass by weight; seed mixture Y is 25 percent ryegrass and 75 % fescue. If a mixture of X and Y contains 30% ryegrass, what percent of the weight of the mixture is X?

A. 10%
B. 33 1/3%
C. 40%
D. 50%
E. 66 2/3%

0.4x+0.25y = 0.3(x+y)
0.4x-0.3x = 0.3y - 0.25y
0.1x=0.05y
or
2x=y So Y=33 1/3 %
Intern
Joined: 29 Jan 2015
Posts: 8
Concentration: Finance, Economics
GPA: 3.7
A feed store sells two varieties of birdseed: Brand A, which  [#permalink]

Show Tags

21 Apr 2015, 01:43
EMPOWERgmatRichC wrote:
Hi JeroenReunis,

Your calculations are correct; you make a mistake in your end deduction though.

When you get to this calculation....

.15Y = .1X

You have a RATIO of X to Y. Here's what you need to do with this ratio to get to the correct answer:

Let's multiply both sides by 100 to get rid of the decimal....

15Y = 10X

From here, you can do work in a couple of different ways. I'm going to continue to do "ratio math"....

15Y = 10X

15/10 = X/Y

3/2 = X/Y

This means that for every 3 "units" of X, we have 2 "units" of Y. So, for every 5 total units, 3/5 are X and 2/5 are Y. The question asks for the percent of the mixture that is X...

3/5 = 60%

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

Hello Rich,

First of all many thanks for your reply, this question can't get out of my mind.
However I still do not get it.

Since 10x = 15y

I would assume that for every 1X there are 1.5Y.
So for every 2X there are 3Y. (Ratio is 2:3)
So in total there are 5 units, X= 2/5 of Total which is 40%.

Even after I put down 10 paperclips (=X) and 15 coins(=Y) on my desk, i still see it as there are 1.5Y for every 1X.

Another example if the ratio of cows to pigs is 2 to 4 than 1C=2P right? How is this any different?

Could you please try to explain to me where my thinking goes wrong? Just don't get it
A feed store sells two varieties of birdseed: Brand A, which   [#permalink] 21 Apr 2015, 01:43

Go to page    1   2    Next  [ 26 posts ]

A feed store sells two varieties of birdseed: Brand A, which

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

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