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Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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28 Nov 2012, 09:13
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Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ? A. 5Kg B. 10Kg C. 12 Kg D. 6Kg
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Last edited by Bunuel on 28 Nov 2012, 09:19, edited 1 time in total.
Renamed the topic and edited the question.



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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28 Nov 2012, 09:30
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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02 May 2013, 12:42
prat29 wrote: Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ?
A. 5Kg B. 10Kg C. 12 Kg D. 6Kg I am very much interested to know how this question be done with alligation method ? I tried, but i am missing some elements. Thanks & Regards Vinni



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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prat29 wrote: Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ?
A. 5Kg B. 10Kg C. 12 Kg D. 6Kg Given information can be rephrased as " Fresh dates contain 10% fruit while dry dates contain 72% fruit" Hence 36 Kg of fresh dates contain 10% of 36 = 3.6 Kg of fruit. This same amount of fruit is present after the dates are dried. If we assume the mass of the dry dates obtained as x Kg, then 72% of x = 3.6 \(0.72*x = 3.6\) Hence x = 5 Kg Option A is the correct answer



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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03 May 2013, 05:09
prat29 wrote: Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ?
A. 5Kg B. 10Kg C. 12 Kg D. 6Kg Responding to a pm: Personally, I would use the method used by Bunuel above. But if you insist on using the "alligation method" which we call "scale method", here is how you can do it: What two things are mixed to give the third? Dry dates are mixed with water to give fresh dates. Dry dates have 28% water, water is 100% water and fresh dates have 90% water. Dry dates/water = w1/w2 = (A2  Aavg)/(Aavg  A1) = (100  90)/(90  28) = 10/62 = 5/31 Mixing 5 kg of dry dates with 31 kg (to maintain consistency) of water will give you 36 kg of fresh dates. Answer 5 kg
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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14 Jul 2013, 00:02
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Fresh dates 36 kg = 90% water and 10% pure dates part. So pure dates part= 36 *0.1= 3.6 kg pure date. Dry dates say x kg = 28% water and 72% pure dates part. So pure dates part= x *0.72= 0.72x kg pure date.
Equate the pure dates part only, since that quantity is same in both mixture,so 0.72 x = 3.6 x= 3.6/0.72 = 360/72 = 5 kg. Ans A



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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21 Jul 2013, 00:59
why can't i resolve this problem by putting together these 2 equations: 1 F=0.9W 2 D=0.28W D= (0.28F)/0.9 i don't understand what is my error



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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21 Jul 2013, 01:49



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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21 Jul 2013, 02:34
prat29 wrote: Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ?
A. 5Kg B. 10Kg C. 12 Kg D. 6Kg 1. Nonwater percentage of fresh grapes and dry grapes are 10% and 72% resp i.e., 7.2 times more in the dry grapes 2. So from 36 kg fresh grapes we can obtain 36/7.2 = 5 kg of dry grapes.
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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23 Jul 2014, 08:53
prat29 wrote: Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ?
A. 5Kg B. 10Kg C. 12 Kg D. 6Kg Just wanted to chip in my 2 cents for the question… Since a fresh date is 10% nonwater and a dry date is 72% nonwater then the ratio of nonwater for the dry date to the nonwater for the fresh date is 10/72 or 5/36. Meaning that for every 36 units of nonwater in a fresh date there is 5 units of nonwater in the dry date. Hence A



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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23 Jul 2014, 21:32
Weight of elements in 36 kg (fresh dates) water=32.4 kg, other 3.6 kg To make dry dates out of it some water has to be removed . Let it be x. Weight (dry dates) water = 32.4 x, other  3.6 kg Proportion of elements(dry dates) water = 28, other 72 (32.4 x) / 3.6 = 28/72 From which we can find weight of water to be 1.4 kg and therefore total weight of dry dates = 5 kg.
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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18 Jun 2015, 22:54
prat29 wrote: Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ?
A. 5Kg B. 10Kg C. 12 Kg D. 6Kg fresh date 90% water 10% no water Dry date 28% water 72% no water need to find weight of fry dates from 36 fresh grapes=let it be x constant is non water portion 36 * 10%=72%x x=5kg



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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04 Jul 2015, 16:16
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Hi,
I tried solving the other way round i.e by equating % of water amount.
0.9 * 36 = 0.28 * d. This doesn't result in 5 kg weight. Why wouldn't this work? Please clarify.



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Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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09 Jul 2015, 21:24
ashtitude wrote: Hi,
I tried solving the other way round i.e by equating % of water amount.
0.9 * 36 = 0.28 * d. This doesn't result in 5 kg weight. Why wouldn't this work? Please clarify. You cannot equate these two because the amount of water is not equal in these two cases. You get dry dates by removing water from fresh dates.
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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08 Aug 2015, 09:22
VeritasPrepKarishma wrote: ashtitude wrote: Hi,
I tried solving the other way round i.e by equating % of water amount.
0.9 * 36 = 0.28 * d. This doesn't result in 5 kg weight. Why wouldn't this work? Please clarify. You cannot equate these two because the amount of water is not equal in these two cases. You get dry dates by removing water from fresh dates. I have the same problem. Can't we divide the total amount of water in 36 kgs across to get the dried grapes?



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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26 Sep 2015, 05:10
dry substance in fresh date:
(10/100)*36=3.6kg
3.6kg = 72% xkg =100%
x=(3.6*100)/72, x=5kg
A



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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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21 Feb 2016, 00:05
weight * concentration = constant w1*c1 = w2*c2 36 * 10/100 = w2 * 72/100 w2 = 5 kg.
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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19 Mar 2017, 21:42
the weight of substance other than water is not changing. Only its concentration is changing. (10*36)/100 = (72*X)/100 X = 5 kg
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Re: Fresh dates contain 90% water while dry dates contain 28% [#permalink]
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19 Mar 2017, 23:47
prat29 wrote: Fresh dates contain 90% water while dry dates contain 28% water . How many kg of dry dates can be obtained from 36kg of fresh dates ?
A. 5Kg B. 10Kg C. 12 Kg D. 6Kg let the weight of dry dates to be obtained be x 36 kg dates have 0.9*36 = 32.4 kg water and 3.6 kg other stuff other stuff will also be (10.28)x equating we get (1  0.28)x = 3.6 or x = 3.6/0.72 = 5kg Option A




Re: Fresh dates contain 90% water while dry dates contain 28%
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