Author 
Message 
TAGS:

Hide Tags

Manager
Joined: 15 Apr 2013
Posts: 83
Location: India
Concentration: Finance, General Management
WE: Account Management (Other)

If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
02 Sep 2013, 09:59
3
This post received KUDOS
51
This post was BOOKMARKED
Question Stats:
61% (01:19) correct 39% (01:18) wrong based on 909 sessions
HideShow timer Statistics
If grapes are 92% water and raisins are 20% water, then how much did a quantity of raisins, which currently weighs 10 pounds, weigh when all the raisins were grapes? (Assume that the only difference between their raisinweight and their grapeweight is water that evaporated during their transformation.) A. 25 pounds B. 46 pounds C. 92 pounds D. 100 pounds E. 146 pounds Spoiler Alert : VeritasPrep Mock Test Question. Though I could get this question right, I took more than 3 minutes. Is there any simpler way to solve this one?
Official Answer and Stats are available only to registered users. Register/ Login.



Math Expert
Joined: 02 Sep 2009
Posts: 43789

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
03 Sep 2013, 04:18
24
This post received KUDOS
Expert's post
47
This post was BOOKMARKED



Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 7934
Location: Pune, India

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
26 Nov 2013, 00:46
5
This post received KUDOS
Expert's post
5
This post was BOOKMARKED
pavan2185 wrote: If grapes are 92% water and raisins are 20% water, then how much did a quantity of raisins, which currently weighs 10 pounds, weigh when all the raisins were grapes? (Assume that the only difference between their raisinweight and their grapeweight is water that evaporated during their transformation.) A. 25 pounds B. 46 pounds C. 92 pounds D. 100 pounds E. 146 pounds Spoiler Alert : VeritasPrep Mock Test Question. Though I could get this question right, I took more than 3 minutes. Is there any simpler way to solve this one? Responding to a pm: Actually, the best method for this question is the one given by Bunuel. I used the same method to give the explanation in the mock too. But you can use weighted average if you wish. Raisins have 20% water. Water is 100% water. You mix these two to make grapes which has 92% water. (This is another way of saying you remove water from grapes to make raisins) In what ratio will you mix them? Wr/Ww = (Cw  Cavg)/(Cavg  Cr) = (100  92)/(92  20) = 8/72 = 1/9 So every 1 unit of raisin will be mixed with 9 units of water to give 10 units of grapes. So 10 pounds of raisins will mix with 90 pounds of water to give 100 pounds of grapes. Answer (D)
_________________
Karishma Veritas Prep  GMAT Instructor My Blog
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews



SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1839
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
03 Apr 2014, 23:10
1
This post received KUDOS
Bunuel wrote: pavan2185 wrote: If grapes are 92% water and raisins are 20% water, then how much did a quantity of raisins, which currently weighs 10 pounds, weigh when all the raisins were grapes? (Assume that the only difference between their raisinweight and their grapeweight is water that evaporated during their transformation.) A. 25 pounds B. 46 pounds C. 92 pounds D. 100 pounds E. 146 pounds Spoiler Alert : VeritasPrep Mock Test Question. Though I could get this question right, I took more than 3 minutes. Is there any simpler way to solve this one? Since only water evaporates, then the weight of pulp (nonwater) in grapes and raisins is the same. Thus 0.08*{weight of grapes}=0.8*{weight of raisins} > 0.08x = 0.8*10 > x = 100. Answer: D. Similar questions to practice: eachofthecucumbersin100poundsofcucumbersiscomposed102354.htmlfivekilogramsoforangescontained98ofwater141401.htmlfreshdatescontain90waterwhiledrydatescontain143245.htmlHope this helps. (Assume that the only difference between their raisinweight and their grapeweight is water that evaporated during their transformation.)Had the above highlighted condition not mentioned, would 46 pounds be the answer.. ?
_________________
Kindly press "+1 Kudos" to appreciate



SVP
Joined: 06 Nov 2014
Posts: 1904

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
11 May 2015, 07:42
6
This post received KUDOS
1
This post was BOOKMARKED
If 92 percent of grapes is water then 8 percent is the fruit. If 20 percent of raisins is water then 80 percent is fruit.
.08 (x pounds) = .8 (10 pounds) x = 100 pounds



Current Student
Joined: 29 Jun 2014
Posts: 20
GPA: 4
WE: Medicine and Health (Health Care)

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
06 Jun 2015, 19:46
Hi I understand the solution given but why is the answer not 46 pounds? why can't one get the answer by proportionality? what is the flaw in my logic?Would appreciate an answer if possible. Thanks so much.



EMPOWERgmat Instructor
Status: GMAT Assassin/CoFounder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 11019
Location: United States (CA)
GRE 1: 340 Q170 V170

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
08 Jun 2015, 21:03
Hi sykhong, Until you show your 'steps', we won't know exactly where you made your mistake. We CAN prove why 46 pounds is NOT the correct answer though.... IF....the grapes weighted 46 pounds total and those grapes were 92% water, then we'd have.... Total = 46 pounds Water = .92(46) = 42.32 pounds NotWater = 3.68 pounds The part that is NOTWATER is key here, since that number does NOT change. The raisins would ALSO contain those 3.68 pounds of notwater, which would represent 80% of the weight (since 20% of the raisins are water). 3.68 = .8(Total Weight) 3.68/.8 = Total Weight 4.6 pounds = Total weight of the raisins However, the prompt tells us that the raisins are supposed to weigh 10 POUNDS, so the 4.6 pounds is clearly TOO LOW and the grapes must weigh MORE than 46 pounds. GMAT assassins aren't born, they're made, Rich
_________________
760+: Learn What GMAT Assassins Do to Score at the Highest Levels Contact Rich at: Rich.C@empowergmat.com
Rich Cohen
CoFounder & GMAT Assassin
Special Offer: Save $75 + GMAT Club Tests Free
Official GMAT Exam Packs + 70 Pt. Improvement Guarantee www.empowergmat.com/
***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************



eGMAT Representative
Joined: 04 Jan 2015
Posts: 806

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
10 Jun 2015, 22:33
3
This post received KUDOS
Expert's post
2
This post was BOOKMARKED
Presenting a slightly alternate approach: Since the weight of water is the difference between raisins and grapes, let's calculate the weight of water in \(10\) pounds of raisins and water's weight in raisins when they were grapes Water in raisinsFor \(10\) pounds of raisins there is \(20\)% of water. Hence amount of water = \(20\)% of \(10 = 2\) pounds. Water in grapes before they evaporatedLet \(x\) pounds be the amount of water that evaporated. So when the raisins were grapes, Total weight of water = \(2 + x\) Total weight of grapes = \(10 + x\) When raisins were grapes, \(\frac{Weight of Water}{Weight of Grapes} = 92\)% i.e. \(\frac{2 + x}{10 + x} = 0.92\). Solving for \(x\) would give \(x = 90\) pounds. Hence total weight of 10 pounds of raisins when they were grapes = \(10 + 90 = 100\) pounds Hope this helps Regards Harsh
_________________
 '4 out of Top 5' Instructors on gmatclub  70 point improvement guarantee  www.egmat.com



Manager
Status: folding sleeves up
Joined: 26 Apr 2013
Posts: 152
Location: India
Concentration: Finance, Strategy
GMAT 1: 530 Q39 V23 GMAT 2: 560 Q42 V26
GPA: 3.5
WE: Consulting (Computer Hardware)

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
14 Nov 2015, 23:11
grape: 92% water & 8% pulp raisin : 20% water and 80% pulp
80% of (total weight of raisin (x)) = 8 (pulp ) x= 10
total weight = 10* (10 pounds) = 100



Current Student
Joined: 12 Aug 2015
Posts: 297
Concentration: General Management, Operations
GMAT 1: 640 Q40 V37 GMAT 2: 650 Q43 V36 GMAT 3: 600 Q47 V27
GPA: 3.3
WE: Management Consulting (Consulting)

If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
06 Dec 2015, 09:45
if we take the grape ratio and apply to it 100 pounds then we will have 92 pounds of water and 8 pounds of pure pulp. the stem says also that out of 10 pounds  8 pounds is pure pulp. hence we look up and see that this amount of pure pulp (8 pounds) used to have 92 corresponding pounds of water when this was grape that is 100 in total
_________________
KUDO me plenty



Intern
Joined: 20 Jan 2014
Posts: 39
Location: United States
GPA: 3.71

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
21 May 2016, 12:26
1
This post received KUDOS
At first glance this questions seems relatively straightforward but I always find these types of questions some what difficult to work out.
But, I think the best way to do it is clearly write down the info you have and use logic to work it out.
So,
Raisins Contain:
20% Water, and 80% Other
For a total of 10lbs.
Therefore, the raisins contain 2lbs of water and 8lbs of other.
Important to note: The question states the other quantity does not change at all.
Grapes contain:
92% water, and 8% other.
8% other is equals to 8lbs. As this 8% is represented by 8lbs of other the 92% must equal 92lbs of water. 92% + 8% = 100%. Therefore, 92lbs + 8lbs = 100lbs. Answer D.



Intern
Joined: 08 Sep 2016
Posts: 4

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
08 Sep 2016, 10:34
Dear All
This is how i tried to solve it.
Letting x equal to the number of pounds of grapes
x * 0.92 * 0.2 should be the pounds of water left after 80% of the water in the grapes evaporates
x * 0.92 * 0.2 = 2 should be equal to pounds of water that is in the raisins. so we should be able to solve for x. but this equation does not lead to any solution.
Where i am making the mistake?
Regards
B



Chat Moderator
Joined: 04 Aug 2016
Posts: 596
Location: India
Concentration: Leadership, Strategy
GPA: 4
WE: Engineering (Telecommunications)

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
14 May 2017, 21:09
Work with options 
Water weight in raisins = 2 units
From the question; water evaporated = grapes weight  raisin weight
let grapes weight = 100; so water weight in grapes = 92 ; since new water weight = 2 so 90 units of water must have evaporated
LHS=90 (water evaporated ) RHS = grapes weight  raisin weight (10010)=90
LHS=RHS
D



Director
Joined: 17 Dec 2012
Posts: 627
Location: India

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
10 Jun 2017, 00:11
pavan2185 wrote: If grapes are 92% water and raisins are 20% water, then how much did a quantity of raisins, which currently weighs 10 pounds, weigh when all the raisins were grapes? (Assume that the only difference between their raisinweight and their grapeweight is water that evaporated during their transformation.) A. 25 pounds B. 46 pounds C. 92 pounds D. 100 pounds E. 146 pounds Spoiler Alert : VeritasPrep Mock Test Question.hough I could get this question right, I took more than 3 minutes. Is there any simpler way to solve this one? 1 The crucial point to understand is that the weight of the non water elements is the same in grapes and raisins. They are just different percentages of different weights but the actual weight is the same. 2. 80% of 10 =8% of x. So x=100.
_________________
Srinivasan Vaidyaraman Sravna http://www.sravnatestprep.com
Premium Material Standardized Approaches



Intern
Joined: 25 Jul 2017
Posts: 14

If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
19 Aug 2017, 11:18
I keep getting thrown off here because I use the following ratios formula:
G/R = 0.08/0.8
Why doesn't this work? The formula works with other ratios (such as when working with similar triangles). Why do we have to make it 0.08G=0.8R instead? Does it have to do with the fact that we're using percentages?



Math Expert
Joined: 02 Sep 2009
Posts: 43789

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
20 Aug 2017, 00:34



Senior Manager
Joined: 29 Jun 2017
Posts: 483
GPA: 4
WE: Engineering (Transportation)

Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]
Show Tags
21 Dec 2017, 10:50
Grapes  > Raisins 8% solid8% solid of Grapes 92% water20% water 10 pound raisins means> water will be 20% of 10 =2 solid will be 102 = 8 now 8 is 8% of grapes Y x 0.08 = 8 Y = 100 OPTION D
_________________
Give Kudos for correct answer and/or if you like the solution.




Re: If grapes are 92% water and raisins are 20% water, then how
[#permalink]
21 Dec 2017, 10:50






