Material A costs $3 per kilogram, and Material B costs$5 : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 21 Jan 2017, 20:02

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Material A costs $3 per kilogram, and Material B costs$5

Author Message
TAGS:

### Hide Tags

Intern
Joined: 09 Feb 2011
Posts: 11
Followers: 0

Kudos [?]: 70 [1] , given: 1

Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

11 Feb 2011, 01:26
1
KUDOS
38
This post was
BOOKMARKED
00:00

Difficulty:

85% (hard)

Question Stats:

51% (02:36) correct 49% (02:02) wrong based on 1481 sessions

### HideShow timer Statistics

Material A costs $3 per kilogram, and Material B costs$5 per kilogram. If 10 kilograms of Material K consists of x kilograms of Material A and y kilograms of Material B, is x > y ?

(1) y > 4
(2) The cost of the 10 kilograms of Material K is less than $40. [Reveal] Spoiler: OA Last edited by Bunuel on 07 Dec 2012, 09:35, edited 2 times in total. Edited the question and added the OA. Math Expert Joined: 02 Sep 2009 Posts: 36590 Followers: 7092 Kudos [?]: 93370 [3] , given: 10557 Re: How to solve this [#permalink] ### Show Tags 11 Feb 2011, 02:50 3 This post received KUDOS Expert's post 9 This post was BOOKMARKED alltimeacheiver wrote: Material A costs$3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y? (1) y > 4 (2) The cost of the 10 kilograms of material K is less than$40

Material A costs $3 per kilogram, and material B costs$5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y?

Given: x+y=10. Question: is x>y?

(1) y > 4. Clearly insufficient: if y=4.5<x=5.5 the answer will be YES but if y=6>x=4 the answer will be NO.

(2) The cost of the 10 kilograms of material K is less than $40 ---> 3x+5y<40, as y=10-x then: 3x+5(10-x)<40 --> 2x>10 --> x>5, so x>y. Sufficient. Answer: B. _________________ Intern Joined: 21 Feb 2011 Posts: 1 Followers: 0 Kudos [?]: 2 [2] , given: 0 new [#permalink] ### Show Tags 10 Mar 2011, 04:42 2 This post received KUDOS Material A cost 3$/kg and B cost 5$/kg. If 10 kg of material K consist of x kg of A and y kg of B, is x>y? 1- y>4 2- the cost of 10kg of K is less than$40.

Solution: -

1) Insufficient
Material A cost 3$/kg and B cost 5$/kg
x+y=10 and y>4 is all we have from statement 1. Since the total price is not fixed, (x,y) can be anything satisfying x+y=10 ....even (5,5) can't be wrong in this case

2) Sufficient
Material A cost 3$/kg and B cost 5$/kg
x+y=10 and the cost of 10kg of K is less than $40. Therefore, 3x+5y<40 => 3x+(10-x)5<40 => 10<2x => 5<x So, x>5 and x+y=10 means x>y Hope it helps !!! _________________ Set out each day believing in your dreams. Know without a doubt that you were made for amazing things. Director Status: Impossible is not a fact. It's an opinion. It's a dare. Impossible is nothing. Affiliations: University of Chicago Booth School of Business Joined: 03 Feb 2011 Posts: 920 Followers: 14 Kudos [?]: 341 [2] , given: 123 Re: How to solve this [#permalink] ### Show Tags 10 Mar 2011, 06:22 2 This post received KUDOS x = 10 - y Rephrasing the question - Is x > y? or Is 10 - y > y Is y < 5 ? 1. Insufficient 2. Sufficient 3x + 5y < 40 3(10 - y) + 4y < 40 2y < 10 Hence y < 5 Hence B. alltimeacheiver wrote: Material A costs$3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x > y? (1) y > 4 (2) The cost of the 10 kilograms of material K is less than$40
Manager
Status: Employed
Joined: 17 Nov 2011
Posts: 100
Location: Pakistan
GMAT 1: 720 Q49 V40
GPA: 3.2
WE: Business Development (Internet and New Media)
Followers: 7

Kudos [?]: 135 [3] , given: 10

### Show Tags

16 Feb 2012, 07:47
3
KUDOS
1
This post was
BOOKMARKED
The answer has to be B.

Let's setup the weighted average equation for this question:

$$x$$ kilograms at 3$per Kilogram $$y$$ kilograms at 5$ per Kilogram
Yields $$10$$ kilograms at z$per Kilogram We also know that $$x+y=10$$ So Equation would be : $$3(x)+5(y)=10(z)$$ Now let's look at the statements: Statement 1: $$y>4$$ Remember: $$x+y=10$$ So: $$x$$ could range between 0 and 6. Insufficient Statement 2: Cost is $$<40$$ So $$3(x)+5(y)<40$$ But $$x+y=10$$ so $$x=10-y$$ So $$3(10-y)+5(y)<40$$ So $$30-2y+5y<40$$ So $$2y<10$$ So $$y<5$$ If $$y<5$$ then $$x>5$$ so $$x>y$$ Sufficient Hence B _________________ "Nowadays, people know the price of everything, and the value of nothing." Oscar Wilde Math Expert Joined: 02 Sep 2009 Posts: 36590 Followers: 7092 Kudos [?]: 93370 [2] , given: 10557 Re: Material A costs$3 per kilogram, and Material B costs $5 [#permalink] ### Show Tags 13 Jun 2013, 01:15 2 This post received KUDOS Expert's post Bumping for review and further discussion*. Get a kudos point for an alternative solution! *New project from GMAT Club!!! Check HERE All DS Mixture Problems to practice: search.php?search_id=tag&tag_id=43 All PS Mixture Problems to practice: search.php?search_id=tag&tag_id=114 _________________ Director Joined: 25 Apr 2012 Posts: 728 Location: India GPA: 3.21 WE: Business Development (Other) Followers: 43 Kudos [?]: 698 [2] , given: 723 Re: Material A costs$3 per kilogram, and Material B costs $5 [#permalink] ### Show Tags 15 Jun 2013, 13:13 2 This post received KUDOS alltimeacheiver wrote: Material A costs$3 per kilogram, and Material B costs $5 per kilogram. If 10 kilograms of Material K consists of x kilograms of Material A and y kilograms of Material B, is x > y ? (1) y > 4 (2) The cost of the 10 kilograms of Material K is less than$40.

Material K cost "C" can be found out by calculating

C= (3*x+5*y)/10

Now the cost C will be close to Material A cost if x is more than y and vice versa

from St 1 we have y>4
For eg y=5, x=5 Cost of Material K will be $4/kg (in between price of Material A and Material B) now if x=4,y=6 ,Cost of material K will be be$ 4.2/kg
if x=1,y=9 then Cost of material will be 4.8$per kg but if we take y=4 and x=6 we get cost of material K as$ 3.8 per kg less than $4 which would have been the price had both material A and B were added equally. Therefore if x>y we should have price of Material K <$ 4kg

Hence St1 alone not sufficient as we can have x=y or x<y

St 2, The cost of the 10 kilograms of Material K is less than $40.[/quote] Cost of Material per kg <$4 which meets our above requirement which means x>y

Therefore ans st B
_________________

“If you can't fly then run, if you can't run then walk, if you can't walk then crawl, but whatever you do you have to keep moving forward.”

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13489
Followers: 576

Kudos [?]: 163 [0], given: 0

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

17 Jul 2014, 07:02
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.
_________________
Intern
Joined: 08 Oct 2014
Posts: 19
Location: Turkmenistan
GMAT 1: 600 Q41 V31
WE: Supply Chain Management (Energy and Utilities)
Followers: 0

Kudos [?]: 15 [0], given: 49

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

27 Oct 2014, 01:21
Bunuel wrote:
alltimeacheiver wrote:
Material A costs $3 per kilogram, and material B costs$5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y?

(1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40 Material A costs$3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y? Given: x+y=10. Question: is x>y? (1) y > 4. Clearly insufficient: if y=4.5<x=5.5 the answer will be YES but if y=6>x=4 the answer will be NO. (2) The cost of the 10 kilograms of material K is less than$40 ---> 3x+5y<40, as y=10-x then: 3x+5(10-x)<40 --> 2x>10 --> x>5, so x>y. Sufficient.

Bunuel,
Can you, please, advise, if the problem stated that x and y can only be integers, would statement 1 be sufficient? I guess YES.
Intern
Joined: 24 Oct 2015
Posts: 1
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

28 Oct 2015, 04:48
1
This post was
BOOKMARKED
I thought that in DS, (1) and (2) could not contradict eachother. However, it seems that they do in this question since

(1) says y> 4 which is the same as y ≥ 5 while

(2) gives us y < 5 which is the same as y ≤ 4

Could someone help me with that ?
Manager
Joined: 26 Jan 2015
Posts: 89
Followers: 0

Kudos [?]: 10 [0], given: 108

Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

28 Nov 2015, 03:50
Bunuel wrote:
alltimeacheiver wrote:
Material A costs $3 per kilogram, and material B costs$5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y?

(1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40 Material A costs$3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y? Given: x+y=10. Question: is x>y? (1) y > 4. Clearly insufficient: if y=4.5<x=5.5 the answer will be YES but if y=6>x=4 the answer will be NO. (2) The cost of the 10 kilograms of material K is less than$40 ---> 3x+5y<40, as y=10-x then: 3x+5(10-x)<40 --> 2x>10 --> x>5, so x>y. Sufficient.

Hi...If in the question it is mentioned that x and y are integers, then will the answer be D? because it will lead to contradiction that 'x is not greater than y' or will still answer be b because (there is no clarity whether x may be equal to y or may be less than y'?
_________________

Kudos is the best way to say Thank you! Please give me a kudos if you like my post

Math Expert
Joined: 02 Sep 2009
Posts: 36590
Followers: 7092

Kudos [?]: 93370 [2] , given: 10557

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

28 Nov 2015, 06:59
2
KUDOS
Expert's post
Alok322 wrote:
Bunuel wrote:
alltimeacheiver wrote:
Material A costs $3 per kilogram, and material B costs$5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y?

(1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40 Material A costs$3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y? Given: x+y=10. Question: is x>y? (1) y > 4. Clearly insufficient: if y=4.5<x=5.5 the answer will be YES but if y=6>x=4 the answer will be NO. (2) The cost of the 10 kilograms of material K is less than$40 ---> 3x+5y<40, as y=10-x then: 3x+5(10-x)<40 --> 2x>10 --> x>5, so x>y. Sufficient.

Hi...If in the question it is mentioned that x and y are integers, then will the answer be D? because it will lead to contradiction that 'x is not greater than y' or will still answer be b because (there is no clarity whether x may be equal to y or may be less than y'?

If we were told that x and y are integers then y > 4 (5, 6, 7, ...) together with x + y = 10, would be sufficient to say that x is NOT greater than y. But in this case the question would be flawed because the statements would contradict each other which never happens in proper GMAT DS questions.

Hope it's clear.
_________________
Intern
Joined: 02 Oct 2014
Posts: 7
Followers: 0

Kudos [?]: 0 [0], given: 9

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

23 Dec 2015, 06:42
Thank you Buennel!

Very important point since i came here with the same problem and i pulled my hair over this for a solid 20 minutes.

If you simplify (2) it results in y < 5. While (1) says that y > 4.

Contradicting? No. We might think its contradictory if we assume that the qty involved are integers (common mistake, since qty usually are).

Do note that the question does not say that x or y are integers. And it is for this reason, otherwise, the question would logically be incorrect.

My takeaway:
1) Always remember that GMAT statements are never contradictory
2) If at some point, it seems like they are contradicting, it could mean
a) i've done it incorrectly
b) they aren't contradicting in the first place! :p
3) In such WP questions, ask yourself, are the quantities divisible into decimals?
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7125
Location: Pune, India
Followers: 2137

Kudos [?]: 13683 [1] , given: 222

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

16 Mar 2016, 06:35
1
KUDOS
Expert's post
alltimeacheiver wrote:
Material A costs $3 per kilogram, and Material B costs$5 per kilogram. If 10 kilograms of Material K consists of x kilograms of Material A and y kilograms of Material B, is x > y ?

(1) y > 4
(2) The cost of the 10 kilograms of Material K is less than $40. Responding to a pm: Quote: In solving the B part of this question (like in many situation i have faced) 3[5]+5[5]=15+25="40<40" This is my question: [Q-1] Can we ever take 40<40 ie x<x when x is same number. Similarly x>x and so on in GMAT? To be honest, I am not sure what your question means. 40 < 40 is not correct and neither is x < x since both are equal. And no, x > x doesn't work either. If they are the same number, one cannot be greater than the other. You might want to show me the steps of where you come across this problem. _________________ Karishma Veritas Prep | GMAT Instructor My Blog Get started with Veritas Prep GMAT On Demand for$199

Veritas Prep Reviews

Intern
Joined: 30 Apr 2015
Posts: 7
Followers: 0

Kudos [?]: 0 [0], given: 14

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

17 Dec 2016, 10:31
Bunuel wrote:
alltimeacheiver wrote:
Material A costs $3 per kilogram, and material B costs$5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y?

(1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40 Material A costs$3 per kilogram, and material B costs $5 per kilogram. If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x >y? Given: x+y=10. Question: is x>y? (1) y > 4. Clearly insufficient: if y=4.5<x=5.5 the answer will be YES but if y=6>x=4 the answer will be NO. (2) The cost of the 10 kilograms of material K is less than$40 ---> 3x+5y<40, as y=10-x then: 3x+5(10-x)<40 --> 2x>10 --> x>5, so x>y. Sufficient.

Hi Bunuel,

Can this be solve via weighted average?
By the formulae n1/n2= (m2-m)/(m-m1)
Intern
Joined: 26 Oct 2016
Posts: 6
Followers: 0

Kudos [?]: 0 [0], given: 1

Re: Material A costs $3 per kilogram, and Material B costs$5 [#permalink]

### Show Tags

08 Jan 2017, 17:51
I thought about this conceptually. Since A costs $3 per kg and B costs$5 per kg, I used that in conjunction with statement 2 to prove sufficiency. In statement 2, 10kg of K is less than $40. Dividing both sides by 10, 1 kg of K is less than$4. Knowing the costs of X and Y, that to me would mean that there would have to be more of A than B to be less than $4 (equal amounts would have it equal$4).

It's not perfect as we could be dealing with integers and you can't assume one of A or B isn't 0....but it's how I went about it.
Re: Material A costs $3 per kilogram, and Material B costs$5   [#permalink] 08 Jan 2017, 17:51
Similar topics Replies Last post
Similar
Topics:
Material M costs $10 per kg, and material N costs$20 per kg. If 25 kg 2 28 Dec 2016, 09:49
1 Material A costs $3 per kilogram, and material B costs$5 per kilogram 1 24 Aug 2016, 07:57
21 The cost of 3 chocolates, 5 biscuits, and 5 ice creams is 15 20 Mar 2011, 07:56
29 Material A costs $3 per kilogram, and material B costs$5 40 13 Aug 2009, 14:55
3 Material A costs $3 per kilogram, and material B costs$5 3 08 Jan 2008, 07:53
Display posts from previous: Sort by