Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 07 Oct 2015, 13:27

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

GMAT Diagnostic Test Question 33

Author Message
Intern
Joined: 13 Jul 2012
Posts: 2
Followers: 0

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

Re: GMAT Diagnostic Test Question 33 [#permalink]  03 Oct 2012, 02:08
bb wrote:
GMAT Diagnostic Test Question 33
Field: word problems (mixture)
Difficulty: 650
 Rating:

A kilogram of nut mixture contains X% chestnuts and Y% walnuts and sells for $7.00/kg. If the ratio of chestnuts is increased by 50% so that the new mixture is sold for$8.00/kg, what is the price of a kg of walnuts?

A. $1.00 B.$2.50
C. $5.00 D.$7.50
E. $10.00 I hate to bump an old thread but isn't there an issue re. what it means to "increase a ratio by 50%"? "Increasing a ratio" by 50% would e.g. involve increasing a ratio of 2:3 to 1:1 (e.g. we go from 0.66*1.5 = 1). THAT is a 50% increase in a ratio. Using a plugging in numbers approach, a movement from a 40% / 60% mixture ratio to a 50% / 50% ratio would represent an increase in the ratio by 50%. Yet this cannot satisfy any of the answer choices. The (1.5X) to (1-1.5X) answer used by gmat tiger is potentially troublesome as it can lead to negative quantities for the Walnut side.  Kaplan Promo Code Knewton GMAT Discount Codes Manhattan GMAT Discount Codes Intern Joined: 02 Apr 2013 Posts: 4 Location: Russian Federation Followers: 0 Kudos [?]: 5 [0], given: 0 Re: GMAT Diagnostic Test Question 33 [#permalink] 06 Apr 2013, 13:43 (a1) X/100=c/(w+c) (a2) Y/100=w/(w+c)=(100-X)/100 (b1) A price of c (b2) B price of w (c1) Ac+Bw=7(c+w) (c2) Ac/(c+w)+Bw/(c+w)=7 (d1) AX/100+B(100-X)/100=7 (d2) A1.5X/100+B(100-1.5X)/100=8 *substitute c/(c+w) with X/100, and w/(w+c) with (100-X)/100 (e1) A0.5X/100-B0.5/100=1 *subtract d1 from d2 (e2) 200=AX-BX (e3) 200+BX=AX (f1) (200+BX)/100+B(100-X)/100=7 *substitute AX in d1 with e3 (f2) 700=200+BX+100B-BX (f3) 500=100B (g1) B=5 *the price of a kg of w To avoid ambiguity stem should have STATED that the "proportion" of c in the mixture OR that the ratio of c to the whole mixture IS increased by 50%. Hope this helps! Intern Joined: 13 Jul 2012 Posts: 2 Followers: 0 Kudos [?]: 0 [0], given: 0 Re: GMAT Diagnostic Test Question 33 [#permalink] 06 Apr 2013, 20:27 Survival wrote: (a1) X/100=c/(w+c) (a2) Y/100=w/(w+c)=(100-X)/100 (b1) A price of c (b2) B price of w (c1) Ac+Bw=7(c+w) (c2) Ac/(c+w)+Bw/(c+w)=7 (d1) AX/100+B(100-X)/100=7 (d2) A1.5X/100+B(100-1.5X)/100=8 *substitute c/(c+w) with X/100, and w/(w+c) with (100-X)/100 (e1) A0.5X/100-B0.5/100=1 *subtract d1 from d2 (e2) 200=AX-BX (e3) 200+BX=AX (f1) (200+BX)/100+B(100-X)/100=7 *substitute AX in d1 with e3 (f2) 700=200+BX+100B-BX (f3) 500=100B (g1) B=5 *the price of a kg of w To avoid ambiguity stem should have STATED that the "proportion" of c in the mixture OR that the ratio of c to the whole mixture IS increased by 50%. Hope this helps! Gotcha. Although it's worth pointing out that the text in the question isn't ambiguous - it's just plain wrong. Your amendments would correct it, however. Manager Status: Looking to improve Joined: 15 Jan 2013 Posts: 177 GMAT 1: 530 Q43 V20 GMAT 2: 560 Q42 V25 GMAT 3: 650 Q48 V31 Followers: 1 Kudos [?]: 52 [0], given: 65 Re: GMAT Diagnostic Test Question 33 [#permalink] 07 Apr 2013, 11:33 How about using some logical reasoning rather than pure algebra. E.g. X% and Y% mixture costs$7 and X% is increased by 50% => 1.5X% in the mixture increases the price by 1$. A 50% increase in X results in a$1 increase in price. This implies the cost X% is $2 since 50% of$2 is $1. Hence the cost for Y% is$7 - $2 =$5.

Any comments on fallacy of this approach...
_________________

KUDOS is a way to say Thank You

Manager
Joined: 06 Feb 2013
Posts: 60
Followers: 1

Kudos [?]: 22 [0], given: 35

Re: GMAT Diagnostic Test Question 33 [#permalink]  17 Sep 2013, 00:46
I wonder if Bunuel or Karishma can provide their ways to this problem... Admittedly, GMAT TIGER's way is fairly clear...just wonder if there is a more concise way. Thanks.
_________________

There are times when I do not mind kudos...I do enjoy giving some for help

Math Expert
Joined: 02 Sep 2009
Posts: 29777
Followers: 4896

Kudos [?]: 53459 [0], given: 8160

Re: GMAT Diagnostic Test Question 33 [#permalink]  17 Sep 2013, 00:51
Expert's post
obs23 wrote:
I wonder if Bunuel or Karishma can provide their ways to this problem... Admittedly, GMAT TIGER's way is fairly clear...just wonder if there is a more concise way. Thanks.

This question is removed from the database.
_________________
Re: GMAT Diagnostic Test Question 33   [#permalink] 17 Sep 2013, 00:51

Go to page   Previous    1   2   3   [ 46 posts ]

Similar topics Replies Last post
Similar
Topics:
3 GMAT Diagnostic Test Question 33 8 06 Jun 2009, 22:18
9 GMAT Diagnostic Test Question 14 30 06 Jun 2009, 21:24
14 GMAT Diagnostic Test Question 11 16 06 Jun 2009, 21:06
34 GMAT Diagnostic Test Question 7 31 06 Jun 2009, 20:53
15 GMAT Diagnostic Test Question 4 37 06 Jun 2009, 20:06
Display posts from previous: Sort by

GMAT Diagnostic Test Question 33

Moderators: WoundedTiger, Bunuel

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.