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# If grapes are 92% water and raisins are 20% water, then how

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If grapes are 92% water and raisins are 20% water, then how [#permalink]  02 Sep 2013, 09:59
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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 raisin-weight and their grape-weight 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?
[Reveal] Spoiler: OA
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Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]  03 Sep 2013, 04:18
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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 raisin-weight and their grape-weight 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 (non-water) 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.

Similar questions to practice:
each-of-the-cucumbers-in-100-pounds-of-cucumbers-is-composed-102354.html
five-kilograms-of-oranges-contained-98-of-water-141401.html
fresh-dates-contain-90-water-while-dry-dates-contain-143245.html

Hope this helps.
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Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]  26 Nov 2013, 00:46
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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 raisin-weight and their grape-weight 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.

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Get started with Veritas Prep GMAT On Demand for $199 Veritas Prep Reviews SVP Status: The Best Or Nothing Joined: 27 Dec 2012 Posts: 1854 Location: India Concentration: General Management, Technology WE: Information Technology (Computer Software) Followers: 31 Kudos [?]: 1363 [0], given: 193 Re: If grapes are 92% water and raisins are 20% water, then how [#permalink] 03 Apr 2014, 23:10 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 raisin-weight and their grape-weight 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 (non-water) 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: each-of-the-cucumbers-in-100-pounds-of-cucumbers-is-composed-102354.html five-kilograms-of-oranges-contained-98-of-water-141401.html fresh-dates-contain-90-water-while-dry-dates-contain-143245.html Hope this helps. (Assume that the only difference between their raisin-weight and their grape-weight 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 GMAT Club Legend Joined: 09 Sep 2013 Posts: 8227 Followers: 419 Kudos [?]: 111 [0], given: 0 Re: If grapes are 92% water and raisins are 20% water, then how [#permalink] 10 May 2015, 08:43 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. _________________ Optimus Prep Instructor Joined: 06 Nov 2014 Posts: 1012 Followers: 14 Kudos [?]: 169 [2] , given: 6 Re: If grapes are 92% water and raisins are 20% water, then how [#permalink] 11 May 2015, 07:42 2 This post received KUDOS Expert's post 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 _________________ # Janielle Williams Customer Support # Special Offer: Save up to$200 + GMAT Club Tests

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Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]  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.
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Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]  06 Jun 2015, 20:39
Expert's post
sykhong wrote:
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.

Hi,
to look at the flaw , you will have to give your solution.
i think where you could be going wrong in proportionality is by reducing the non water portion too in same ratio. It is clearly given that the loss is only of water portion, so non water portion will remain the same....
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Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]  08 Jun 2015, 21:03
Expert's post
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
Not-Water = 3.68 pounds

The part that is NOT-WATER is key here, since that number does NOT change.

The raisins would ALSO contain those 3.68 pounds of not-water, 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.

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Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]  10 Jun 2015, 22:33
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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 raisins
For $$10$$ pounds of raisins there is $$20$$% of water. Hence amount of water = $$20$$% of $$10 = 2$$ pounds.

Water in grapes before they evaporated
Let $$x$$ 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

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If grapes are 92% water and raisins are 20% water [#permalink]  11 Aug 2015, 10:16
If grapes are 92% water and raisins are 20% water by weight, 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 raisin-weight and their grape-weight is water that evaporated during their transformation.)

A. 25 pounds

B. 46 pounds

C. 92 pounds

D. 100 pounds

E. 146 pounds
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If grapes are 92% water and raisins are 20% water, then how [#permalink]  11 Aug 2015, 10:38
mkarthik1 wrote:
If grapes are 92% water and raisins are 20% water by weight, 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 raisin-weight and their grape-weight is water that evaporated during their transformation.)

A. 25 pounds

B. 46 pounds

C. 92 pounds

D. 100 pounds

E. 146 pounds

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Re: If grapes are 92% water and raisins are 20% water, then how [#permalink]  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
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If grapes are 92% water and raisins are 20% water, then how [#permalink]  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
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If grapes are 92% water and raisins are 20% water, then how   [#permalink] 06 Dec 2015, 09:45
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