Material A costs $3 per kilogram, and material B costs$5 : GMAT Data Sufficiency (DS) - Page 2
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# Material A costs $3 per kilogram, and material B costs$5

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

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06 Dec 2009, 09:45
kp1811 wrote:
2.cost of K per kg is less than $4 which means A will be more. hence suff I didn't get this one. Can you kindly explain in detail? _________________ Senior Manager Joined: 30 Aug 2009 Posts: 286 Location: India Concentration: General Management Followers: 3 Kudos [?]: 163 [0], given: 5 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 06 Dec 2009, 09:58 Hussain15 wrote: kp1811 wrote: 2.cost of K per kg is less than$4 which means A will be more. hence suff

I didn't get this one. Can you kindly explain in detail?

lets consider the below cases

if x and y are equal i.e. 5kg then avg price of K will be = x* price of A + y* price of B =
(5* 3 + 5*5)/10 = $4/kg. now let x be 4kg then y is 6kg so avg price will be = (4* 3 + 6*5)/10 =$4.2/kg

if x is 6kg then y is 4kg then avg price will be ( 6*3+ 4*5)/10 = $3.8/kg so we can see that only if x>y then cost of K will be less than$4

note: avg price of K is same as cost of K
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Re: Material A costs $3 per kilogram, and material B costs$5 per kilogram [#permalink]

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21 Sep 2010, 10:33
udaymathapati 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. I did it slightly differently. We know x + y = 10... (1) Clearly insufficient. (2) If x = y = 5, then the 10kg of material K costs ($3*5) + ($5*5) =$40. Since x costs less than y, the more you increase x, the less material K will cost. So if K costs less than $40, x must be greater than 5, and so y is less than 5. Sufficient. Manager Joined: 26 Jul 2010 Posts: 103 Location: India Concentration: Operations, General Management Schools: IIMA (M) GMAT 1: 640 Q48 V29 GMAT 2: 670 Q49 V31 WE: Supply Chain Management (Military & Defense) Followers: 6 Kudos [?]: 26 [0], given: 6 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 22 Apr 2011, 22:27 answer is B question simplifies to x+y=10 is x>y 1. y >4 is x> y so we have y=4.5 then x= 5.5 yes y= 5 then x= 5 no y= 6 then x=4 no in sufficent 2. gives 3x+5y<40 and x,y>0 so we have 3(10-y) +5y < 40 y<5 now for all values of y<5 === x> y since x+y=10 hence B _________________ lets start again Math Forum Moderator Joined: 20 Dec 2010 Posts: 2021 Followers: 161 Kudos [?]: 1705 [0], given: 376 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 22 Apr 2011, 22:50 tejal777 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.

umm...(D) is it??

(1) y>4
y=4.1kg; x=4.2kg
x=4.2kg; y=4.2kg
Not Sufficient.

(2)
y=1kg; x=2kg; cost=2*3+1*5=11<40
y=2kg; x=1kg; cost=2*1+2*5=12<40
Not Sufficient.

Combining both:
y=4.5;x=5; cost=5*3+4.5*5=15+22.5=37.5<40
y=5;x=1; cost=1*3+5*5=3+25=28<40
Not Sufficient.

Ans:"E"

P.S.: It is not given that material k contains ONLY material A and B. Had it been given, "B" alone would have sufficed.
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Re: Material A costs $3 per kilogram, and material B costs$5 per kilogram [#permalink]

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22 Apr 2011, 22:57

remember x+y=10 in question statement
_________________

lets start again

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

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23 Apr 2011, 01:54
fluke wrote:
tejal777 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. umm...(D) is it?? (1) y>4 y=4.1kg; x=4.2kg x=4.2kg; y=4.2kg Not Sufficient. (2) y=1kg; x=2kg; cost=2*3+1*5=11<40 y=2kg; x=1kg; cost=2*1+2*5=12<40 Not Sufficient. Combining both: y=4.5;x=5; cost=5*3+4.5*5=15+22.5=37.5<40 y=5;x=1; cost=1*3+5*5=3+25=28<40 Not Sufficient. Ans:"E" P.S.: It is not given that material k contains ONLY material A and B. Had it been given, "B" alone would have sufficed. if it says item k consist of A and B i hope it means it consists of a and b only otherwise so many GMAT would have answer as E this question will too simple to answer if assume what you are saying AM i correct _________________ lets start again Math Forum Moderator Joined: 20 Dec 2010 Posts: 2021 Followers: 161 Kudos [?]: 1705 [0], given: 376 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 23 Apr 2011, 02:20 kamalkicks wrote: if it says item k consist of A and B i hope it means it consists of a and b only otherwise so many GMAT would have answer as E this question will too simple to answer if assume what you are saying AM i correct My intention is not to debunk this question as many agree with the OA to be "B", making your interpretation correct . But it would definitely be less ambiguous if the author mentioned the fact explicitly, at least for me. I consider all of the three statements correct: Sulphuric Acid, $$H_2SO_4$$, consists hydrogen and sulphur. Water, $$H_2O$$, consists only hydrogen and oxygen. Water, $$H_2O$$, consists hydrogen and oxygen. _________________ Director Joined: 01 Feb 2011 Posts: 755 Followers: 14 Kudos [?]: 115 [0], given: 42 Re: Material A costs$3 per kilogram, and material B costs $5 per kilogram [#permalink] ### Show Tags 23 Apr 2011, 06:26 x+y = 10 x>y? 10-y>y => y<5? 1. Insufficient y>4 doesnt mean y <5. y = 4.5 <5 y = 5 is not less than 5 2. Sufficient 3x+5y <40 => 3(10-y)+5y <40 => y <5 Answer is B. Manager Joined: 11 Dec 2010 Posts: 115 WE: Consulting (Consulting) Followers: 4 Kudos [?]: 37 [0], given: 50 Re: Material A costs$3 per kilogram, and material B costs $5 per kilogram [#permalink] ### Show Tags 23 Apr 2011, 06:58 Statement 1 - Not possible to get any single answer as y could be 4.5 or even 5.5 Statement 2 - If x=y, then the cost of 10 kgs would be 40 If it is less than 40 means that quantity of y (higher priced item) is less than X (lower priced) So with statement B, a unique solution can be derived No need for equations... only think logically... SVP Joined: 16 Nov 2010 Posts: 1672 Location: United States (IN) Concentration: Strategy, Technology Followers: 33 Kudos [?]: 514 [0], given: 36 Re: Material A costs$3 per kilogram, and material B costs $5 per kilogram [#permalink] ### Show Tags 24 Apr 2011, 06:36 3x + 5y x + y = 10 (1) y > 4 But x = 5, y = 5 is possible y = 4.5 x = 5.5 is possible (2) 3x + 5y < 40 3(10 - y) + 5y < 40 2y < 10 y < 5 So x > y - sufficient Answer - B _________________ Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant) GMAT Club Premium Membership - big benefits and savings SVP Joined: 16 Nov 2010 Posts: 1672 Location: United States (IN) Concentration: Strategy, Technology Followers: 33 Kudos [?]: 514 [0], given: 36 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 24 Apr 2011, 06:39 3x + 5y x + y = 10 (1) y > 4 But x = 5, y = 5 is possible y = 4.5 x = 5.5 is possible (2) 3x + 5y < 40 3(10 - y) + 5y < 40 2y < 10 y < 5 So x > y - sufficient Answer - B _________________ Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant) GMAT Club Premium Membership - big benefits and savings Director Joined: 01 Feb 2011 Posts: 755 Followers: 14 Kudos [?]: 115 [0], given: 42 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 24 Apr 2011, 07:11 1. Not sufficient y > 4 y 6 4.5 x 4 5.5 x<y x>y 2. Sufficient 3x +5y <40 30-3y+5y <40 y<5 y 4.5 4 x 5.5 6 x>y x>y Answer is B. Manager Joined: 23 Oct 2011 Posts: 84 Followers: 0 Kudos [?]: 74 [0], given: 34 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 25 Oct 2011, 06:01 fluke wrote: Warlock007 wrote: Dear Fluke now that we have that the total quantity is 10 kg so clearly y=10-x so total cost of the mixture 3x+5(10-x)=50-2x (1) y>4 i.e. 10-x>4 so x<6 clearly there can be values of both x & y =5 so in this case x=y no sufficient (2) says 50-2x<40 so x>5 so by this we get y<5 so clearly y<x to make the cost less than 40 B is the answer please correct me You are correct. I just abortively tried to make a point. Fluke? why is the correct answer B? From your previous post I understood that it is E. I agree with your previous post where you said that it should have said "it consists of ONLY x and y..." to be correct. Could you please elaborate on that? Math Forum Moderator Joined: 20 Dec 2010 Posts: 2021 Followers: 161 Kudos [?]: 1705 [0], given: 376 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 25 Oct 2011, 08:56 SonyGmat wrote: Fluke? why is the correct answer B? From your previous post I understood that it is E. I agree with your previous post where you said that it should have said "it consists of ONLY x and y..." to be correct. Could you please elaborate on that? Precisely so. Answer should be "E" as per my interpretation of the wordings. I just surrendered half-heartedly to "B" :D I recommend you skip this question. GMAT's wordings will be very precise and without ambiguity. _________________ Director Status: No dream is too large, no dreamer is too small Joined: 14 Jul 2010 Posts: 651 Followers: 42 Kudos [?]: 864 [0], given: 39 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 11 Dec 2011, 09:13 This is an og problem DS 101 12th edition. Ans. B subhashghosh did good job. _________________ Collections:- PSof OG solved by GC members: http://gmatclub.com/forum/collection-ps-with-solution-from-gmatclub-110005.html DS of OG solved by GC members: http://gmatclub.com/forum/collection-ds-with-solution-from-gmatclub-110004.html 100 GMAT PREP Quantitative collection http://gmatclub.com/forum/gmat-prep-problem-collections-114358.html Collections of work/rate problems with solutions http://gmatclub.com/forum/collections-of-work-rate-problem-with-solutions-118919.html Mixture problems in a file with best solutions: http://gmatclub.com/forum/mixture-problems-with-best-and-easy-solutions-all-together-124644.html Intern Joined: 14 Oct 2011 Posts: 4 Followers: 0 Kudos [?]: 0 [0], given: 4 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 16 Feb 2012, 07:08 tejal777 wrote: Ohh!! People this is why I bow down to this forum...Thank you..! Tejal: Please don't get bow down. The answere is E. Take 1st statement: X= 5.1 and Y= 4.9, here X>Y X= 5 and Y=5 X=Y X=4 and Y= 6 X<Y Hence 1 is not sufficient Take Statement 2: 3X+4Y< 40 Lets take X=6 and Y=4 total cost = 34<40 Take x= 4 and Y= 6 Total Cost= 38<40 Cannot determined x and y,henec not sufficient Combine both: Y=5,X=5 3X+4Y= 33<40 Y= 4.1 X= 5.9 3X+4Y= 34.1 <40 Not sufficient. Some of my friends have argued that there is nothing mentioned like mixture consists of only A and B. This factor would add further uncertainity. Hence E is the best answere according to me. Math Expert Joined: 02 Sep 2009 Posts: 36601 Followers: 7097 Kudos [?]: 93472 [0], given: 10563 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 16 Feb 2012, 08:45 jaymin1986 wrote: tejal777 wrote: Ohh!! People this is why I bow down to this forum...Thank you..! Tejal: Please don't get bow down. The answere is E. Take 1st statement: X= 5.1 and Y= 4.9, here X>Y X= 5 and Y=5 X=Y X=4 and Y= 6 X<Y Hence 1 is not sufficient Take Statement 2: 3X+4Y< 40 Lets take X=6 and Y=4 total cost = 34<40 Take x= 4 and Y= 6 Total Cost= 38<40 Cannot determined x and y,henec not sufficient Combine both: Y=5,X=5 3X+4Y= 33<40 Y= 4.1 X= 5.9 3X+4Y= 34.1 <40 Not sufficient. Some of my friends have argued that there is nothing mentioned like mixture consists of only A and B. This factor would add further uncertainity. Hence E is the best answere according to me. The OA for this question is B, not E. Open discussion of the question is here: material-a-costs-3-per-kilogram-and-material-b-costs-82349.html In case of any question please continue discussion there. _________________ GMAT Club Legend Joined: 09 Sep 2013 Posts: 13505 Followers: 577 Kudos [?]: 163 [0], given: 0 Re: Material A costs$3 per kilogram, and material B costs $5 [#permalink] ### Show Tags 13 Oct 2014, 07:24 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. _________________ Director Joined: 23 Jan 2013 Posts: 579 Schools: Cambridge'16 Followers: 1 Kudos [?]: 42 [0], given: 40 Re: Material A costs$3 per kilogram, and material B costs $5 per kilogram [#permalink] ### Show Tags 27 Nov 2014, 21:52 St1. INSUFFICIENT St.2 means that mixture average cost is 40/10<4$/kg.

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