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A committee is reviewing a total of 20x blackandwhite film [#permalink]
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07 Jul 2013, 08:48
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A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects (y/x)% of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question!
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Last edited by hazelnut on 15 Oct 2017, 00:48, edited 2 times in total.
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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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07 Jul 2013, 08:50
kingflo wrote: A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects % of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question! Dude are you sure you are not missing anything in the highlighted portion?
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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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07 Jul 2013, 09:07
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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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07 Jul 2013, 09:37
Vips0000 wrote: kingflo wrote: A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects % of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question! Dude are you sure you are not missing anything in the highlighted portion? Sorry Vips0000, I had already hit "submit" when I realized that the fraction had not copied correctly. And then the topic was locked. But thanks to Bunuel the confusion did not last too long



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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07 Jul 2013, 09:49
Bunuel wrote: kingflo wrote: A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects y/x% of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question! Say x=y=10. In this case we would have: 20x=200 blackandwhite films; 6y=60 color films. y/x%=10/10%=1% of the blackandwhite films, so 2 blackandwhite films and all 60 color films, thus total of 62 films were selected. Color films thus compose 60/62=30/31 of the selected films. Answer: E. Hope it's clear. P.S. Please read carefully and follow: rulesforpostingpleasereadthisbeforeposting133935.html Pay attention tot he rule #3. Thank you.Hi Bunuel, is there an algebraic way for doing this?



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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07 Jul 2013, 10:01
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Spaniard wrote: Bunuel wrote: Say x=y=10. In this case we would have: 20x=200 blackandwhite films; 6y=60 color films. y/x%=10/10%=1% of the blackandwhite films, so 2 blackandwhite films and all 60 color films, thus total of 62 films were selected. Color films thus compose 60/62=30/31 of the selected films. Answer: E. Hope it's clear. P.S. Please read carefully and follow: rulesforpostingpleasereadthisbeforeposting133935.html Pay attention tot he rule #3. Thank you.Hi Bunuel, is there an algebraic way for doing this? Sure there is.. Total Selected films = 20x* (y/x)% + 6y = 20y/100 +6y =31y/5 Color films = 6y Fraction required in question = 6y / (31y/5) = 30/31 Ans E it is..
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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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22 Oct 2013, 09:12
Bunuel wrote: kingflo wrote: A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects y/x% of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question! Say x=y=10. In this case we would have: 20x=200 blackandwhite films; 6y=60 color films. y/x%=10/10%=1% of the blackandwhite films, so 2 blackandwhite films and all 60 color films, thus total of 62 films were selected. Color films thus compose 60/62=30/31 of the selected films. Answer: E. Hope it's clear. P.S. Please read carefully and follow: rulesforpostingpleasereadthisbeforeposting133935.html Pay attention tot he rule #3. Thank you.I thought 10%/10%=100%, also, what if x and y don't equal each other, like say x is 10,000 and y is 3. let's say X=30 here, and y =4; you get 600 B&W films, and 24 color. y/x%=~13.333%, so 13.333% of 600 B&W films = 80 B&W and 24 color. You can't solve this problem for sure, you could get any number you wanted by just changing what x and y equal, there's two variables here. You could come up with values that gave you any of the answers.



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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22 Oct 2013, 09:19
AccipiterQ wrote: Bunuel wrote: kingflo wrote: A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects y/x% of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question! Say x=y=10. In this case we would have: 20x=200 blackandwhite films; 6y=60 color films. y/x%=10/10%=1% of the blackandwhite films, so 2 blackandwhite films and all 60 color films, thus total of 62 films were selected. Color films thus compose 60/62=30/31 of the selected films. Answer: E. Hope it's clear. P.S. Please read carefully and follow: rulesforpostingpleasereadthisbeforeposting133935.html Pay attention tot he rule #3. Thank you.I thought 10%/10%=100%, also, what if x and y don't equal each other, like say x is 10,000 and y is 3. If x=y, then x/y=1. How else? Next, I chose smart numbers which are easy to plug. You can try and proceed with x=10,000 and y=3.
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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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10 Jan 2014, 09:04
kingflo wrote: A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects y/x% of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question! Use smart numbers for this one y=100 x=2 Then Color films 600 Black and White are 20 Color/Total = 600/620=30/31 E



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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02 Sep 2014, 06:34
i got different results by plugging x=20 , y=10
b&w= 400 colored= 60
selected B&W= 10/20 x 400=200
fraction of colored films= 60/260=3/13
please advise what did i do wrong



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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02 Sep 2014, 07:02
Kholoud wrote: i got different results by plugging x=20 , y=10
b&w= 400 colored= 60
selected B&W= 10/20 x 400=200
fraction of colored films= 60/260=3/13
please advise what did i do wrong It's y/x percent not y/x. A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects y/x% of the blackandwhite films and all of the color films, what fraction of the selected films are in color?A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 If x=20 and y=10. Then: 20x=400 blackandwhite films; 6y=60 color films. y/x%=10/20%=0.5% of the blackandwhite films, so 2 blackandwhite films and all 60 color films, thus total of 62 films were selected. Color films thus compose 60/62=30/31 of the selected films. Answer: E.
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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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02 Sep 2014, 15:22
Bunuel: what's wrong with the following? This is where I seem to go wrong (y/x%) = (y/x/100) which is 100y/x?



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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02 Sep 2014, 19:09



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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31 Mar 2016, 17:06
Attached is a visual that should help.
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Screen Shot 20160331 at 6.06.03 PM.png [ 121.6 KiB  Viewed 2698 times ]
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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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01 Jul 2016, 11:12
Misinterpreted the question and went for C because I thought of all the possible films. smh



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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01 Jul 2016, 14:05
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So you can simply pick any crazy numbers you want for x and y? 1) why does this work 2) how would you recognize that this works?



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Re: A committee is reviewing a total of 20x blackandwhite film [#permalink]
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21 May 2017, 19:01
kingflo wrote: A committee is reviewing a total of 20x blackandwhite films and 6y color films for a festival. If the committee selects y/x% of the blackandwhite films and all of the color films, what fraction of the selected films are in color? A. 1/130 B. 1/5 C. 3/13 D. 10/13 E. 30/31 Had a "not so good" time with this question! There are many ways to tackle this problem, but I think mine achieves relative speed and reliability. First create a table with all movies in column 1, selected movies in column 2, B/W in row 1, and color in row 2. Then fill in the grid. The tricky part here is that the total number of black and white films is equal to y/x PERCENT of 20x, so we need to write down the following algebraic translation: y/x*1/100*20x. The division by 100 turns y/x into a percent instead of a fraction or ratio. Then we need to solve for the share of color films of total selected films: 6y/(6y + y/x*1/100*20x) This part reduces to 6y/(6y+y/5), then to 6y/(31y/5, then to 30y/31y or 30/31.




Re: A committee is reviewing a total of 20x blackandwhite film
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