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The ratio, by volume, of soap to alcohol to water in a [#permalink]
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The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain? A. 50 B. 200 C. 400 D. 625 E. 800
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Originally posted by droopy57 on 16 Aug 2008, 13:57.
Last edited by Bunuel on 26 Apr 2012, 09:25, edited 1 time in total.
Edited the question and added the OA



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Re: PS: Ratio by volume [#permalink]
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droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
(a) 50 (b) 200 (c) 400 (d) 625 (e) 800
Please explain answers, shortcuts, etc. Thanks!! soap:alcohol Intial ratio soap:alcohol: water > 2:50:100 Inital soap:alcohol = 2/50 =2:50 after doubled soap:alcohol =2* 2/50 = 4:50 Initial soap:water = 2/100=2:100 after halved soap:water: 1/2 * 2/100 = 1/100 = 1:100= 4:400 After soap: alcohol:water > 4:50:400 given alchol 100 cumeter. ratio is 8:100:800 (4:50:400) For 100 cu meter of Alcohol 800 cu m water is required.
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Originally posted by x2suresh on 16 Aug 2008, 14:32.
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Re: PS: Ratio by volume [#permalink]
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intial soap to alcohol = 2/50 final soap to alcohol = 4/50 = 2/25
initial soap to water = 2/100 final soap to water = 2/200
in fianl solution soap = 2x, alcohol = 25x, and water = 200x
as per question 25x=100, x = 4
water = 200 * 4 = 800 option E



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Re: PS: Ratio by volume [#permalink]
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new values are S:w=1:100 S:A=2:25 a:s:w=25:2:200
100=25/227*total amnt total amount=4*227
water content=200/227(4*227)=800



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Re: PS: Ratio by volume [#permalink]
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droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
(a) 50 (b) 200 (c) 400 (d) 625 (e) 800
Please explain answers, shortcuts, etc. Thanks!! Given: \(\frac{s}{{\frac{a}{w}}}=\frac{2}{{\frac{50}{100}}}\); The ratio of soap to alcohol is doubled > \(\frac{s}{a}=2*\frac{2}{50}=\frac{4}{50}\); The ratio of soap to water is halved > \(\frac{s}{w}=\frac{1}{2}*\frac{2}{100}=\frac{1}{100}=\frac{4}{400}\); New ratio: \(\frac{s}{{\frac{a}{w}}}=\frac{4}{{\frac{50}{400}}}\) > \(\frac{a}{w}=\frac{50}{400}\) > if \(a=2*50=100\) then \(w=2*400=800\). Answer: E.
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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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INITIAL S:A:W 2:50:100 DOUBLED AND HALVED S:A:W 4:50: 1::100 OR 4::400 so A/W=50/400 100/x=50/400 x=800
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Re: PS: Ratio by volume [#permalink]
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Bunuel wrote: droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
(a) 50 (b) 200 (c) 400 (d) 625 (e) 800
Please explain answers, shortcuts, etc. Thanks!! Given: \(\frac{s}{{\frac{a}{w}}}=\frac{2}{{\frac{50}{100}}}\); The ratio of soap to alcohol is doubled > \(\frac{s}{a}=2*\frac{2}{50}=\frac{4}{50}\); The ratio of soap to water is halved > \(\frac{s}{w}=\frac{1}{2}*\frac{2}{100}=\frac{1}{100}=\frac{4}{400}\); New ratio: \(\frac{s}{{\frac{a}{w}}}=\frac{4}{{\frac{50}{400}}}\) > \(\frac{a}{w}=\frac{50}{400}\) > if \(a=2*50=100\) then \(w=2*400=800\). Answer: E. How you get 1/100=4/400?? Why you multiply by 4??



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Re: PS: Ratio by volume [#permalink]
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Marchikn wrote: Bunuel wrote: droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
(a) 50 (b) 200 (c) 400 (d) 625 (e) 800
Please explain answers, shortcuts, etc. Thanks!! Given: \(\frac{s}{{\frac{a}{w}}}=\frac{2}{{\frac{50}{100}}}\); The ratio of soap to alcohol is doubled > \(\frac{s}{a}=2*\frac{2}{50}=\frac{4}{50}\); The ratio of soap to water is halved > \(\frac{s}{w}=\frac{1}{2}*\frac{2}{100}=\frac{1}{100}=\frac{4}{400}\); New ratio: \(\frac{s}{{\frac{a}{w}}}=\frac{4}{{\frac{50}{400}}}\) > \(\frac{a}{w}=\frac{50}{400}\) > if \(a=2*50=100\) then \(w=2*400=800\). Answer: E. How you get 1/100=4/400?? Why you multiply by 4?? We have that s/a=4/50 (s corresponds to 4) and s/w=1/100 (s corresponds to 1). To get s/a/w ratio we need s to correspond to the same number in both ratio, so we multiply 1/100 by 4 to get s/w=4/100.
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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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18 Apr 2014, 23:51
S:A:W= 2:50:100 S:A = 4:50 S:W = 2:200 = 4:400 Combining above two, 4:50:400 => 8:100:800 Hence (E)
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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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20 Jul 2014, 11:33
S:A:W = 2:50:100
New solution ratios
S: A = 2*2/50= 2/25
S:W = 2/100 *1/2=. 2/200
So New ratio is
2:25:200 Given that alcohol content is 100cc in the new solution.
Let soap ratio be 2x, alcohol ratio be 25 x and water ratio be 200x in the total solution.
It's already given that alcohol content is 100, so equate 25x = 100. => x= 4
Therefore water content will be 200x = 200*4 = 800.



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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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I am using the unknown mupltiplier method for 3 quantities for such problems.
Initial ratios: S:A:W 2:50:100
From stem: (2/50)2=4/50= 2/25 (2/100)/2=2/200=1/100
Then we use the above mentioned approach like this:
S___A___W 2__25___W > This is the new ratio for S and A 1__A___100> This is the new ration for S and W
What we need to do now is create a common denominator for S, as we have 2 different values: LCM of 1 and 2 is 2, so we multiply the first row by 1 (since it already is 2) and the second row by 2 (since it is 1):
S___A___W>S___A___W 2__25___W >2__25___W (*1) 1__A___100>2__25__200 (*2). A just goes down because there was no value there are we already have this ratio.
Now normally you would have the amount for the whole such as this:
S___A___W__ 2x+25x+200x= the given amount.
Now we have that 25x=100>x=4 Then 200x = 200*4=800. ANS E



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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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30 Dec 2015, 11:20
x2suresh wrote: droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
(a) 50 (b) 200 (c) 400 (d) 625 (e) 800
Please explain answers, shortcuts, etc. Thanks!! soap:alcohol Intial ratio soap:alcohol: water > 2:50:100 Inital soap:alcohol = 2/50 =2:50 after doubled soap:alcohol =2* 2/50 = 4:50 Initial soap:water = 2/100=2:100 after halved soap:water: 1/2 * 2/100 = 1/100 = 1:100= 4:400 After soap: alcohol:water > 4:50:400 given alchol 100 cumeter. ratio is 8:100:800 (4:50:400) For 100 cu meter of Alcohol 800 cu m water is required. How do we know only to multiply by soap ratio for the first few steps?



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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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13 Jul 2016, 07:32
droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
A. 50 B. 200 C. 400 D. 625 E. 800 The first thing we want to do is set up the ratio of the original solution using variable multipliers. soap : alcohol : water = 2x : 50x : 100x We are given that the ratio of soap to alcohol is doubled. Our original ratio of soap to alcohol is: soap/alcohol = 2x/50x = x/25x (Notice that we only canceled the 2 and 50; we didn’t cancel the x because it’s our ratio multiplier.) If we double the ratio we multiply the entire ratio by 2, so we have: 2(x/25x) = 2x/25x So now our new ratio is: soap/alcohol = 2x/25x Next we are given that the ratio of soap to water is halved. Our original ratio of soap to water is: soap/water = 2x/100x = x/50x If we halve the ratio, we multiply the entire ratio by 1/2, so we have: (1/2)(x/50x) = x/100x So now our new ratio is: soap/water = x/100x Next we must notice that the amount of soap in the two new ratios is not the same value. In the first new ratio, soap = 2x and in the second new ratio, soap = x. Thus, we need to make these values equal before continuing to the answer. To do this, we multiply the second ratio by 2/2, so we have: soap/water = (2/2)(x/100x) = 2x/200x Now we can set up the ratio of the altered solution. soap : alcohol : water = 2x : 25x : 200x Lastly, we are given that the altered solution will contain 100 cubic centimeters of alcohol. With this we can set up the following equation and determine x: 25x = 100 x = 4 (This means that the ratio multiplier is 4.) Thus, the altered solution will contain (200)(4) = 800 cubic centimeters of water. Answer is E.
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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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20 Jul 2016, 04:58
s:a:w=2:50:100 step 1 ratio of soap to alcohol is doubled = s1/a1=2*s/a=4/50
step 2 Ratio of soap to water is halved = s2/w2=1/2(2/100)=2/200
replace the values back to original
final ratio = s:a:w=4:50:400
final solution = 100 cc of alcohol ,which is 2*50 therefore water = 2*40=800



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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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20 Jul 2016, 19:58
droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
A. 50 B. 200 C. 400 D. 625 E. 800 soap:alcohol is doubled implies the ratio is 4:50:100 Also, soap :water is halved implies the ratio is 4:50:400 So when alcohol is 100 cubic cm, water is 800 cubic cm.
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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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I think this problem can be solved with accuracy by setting up a table. Please see the attached table. The table is self explanatory. Let know if an explanation needed. Answer = 800 option E
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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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soap=2x alcohol=50x water=100x
new soap=4x new alcohol=50x new water=400x
50x=100 so 400x=8(50x)=8(100)=800



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Re: The ratio, by volume, of soap to alcohol to water in a [#permalink]
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24 Dec 2017, 12:15
droopy57 wrote: The ratio, by volume, of soap to alcohol to water in a certain solution is 2:50:100. The solution will be altered so that the ratio of soap to alcohol is doubled while the ratio of soap to water is halved. If the altered solution will contain 100 cubic centimeters of alcohol, how many cubic centimeters of water will it contain?
A. 50 B. 200 C. 400 D. 625 E. 800 S:A:W=2:50:100 =>S/A=2x/50x  new ratio =4x/50x =>S/W=2x/100x  new ratio =x/100x So, A/S=50x/4x and, W/S=100x/x or 400x/4x Therefore, new S:A:W=4:50:400 Now A=100 =>50x=100 =>x=2 Thus, W=400x=400*2=800; Answer=E
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