Sponsored Ad:
Results 1 to 10 of 10

Thread: one of mixtures

  1. #1
    An Urch Guru Pundit Swami Sage
    Join Date
    Nov 2002
    Location
    Peru
    Posts
    613
    Rep Power
    20


    Good post? Yes | No

    one of mixtures

    Sponsored Ad:
    Container A and Container B both contain a mixture of alcohol and water. The ratio of alcohol to water in container A is 1 to 3. The ratio of alcohol to water in container B is 1 to 9. 8 ounces of the mixture in container A is taken and mixed into container B. Then, 16 ounces of the mixture in container B is taken and mixed into container A. If both containers originally contained 40 ounces of mixture, what is the final ratio of alcohol to water in container A?

    A. 1:7

    B. 2:7

    C. 5:19

    D. 1:3

    E. 10:27

  2. #2
    An Urch Guru Pundit Swami Sage greycellz's Avatar
    Join Date
    Feb 2005
    Location
    New Jersey
    Posts
    855
    Rep Power
    19


    Good post? Yes | No

    Re: one of mixtures

    C.
    Container A has Alcohol:Water in 1:3 ratio. i.e. 1/4th alcohol out of 40oz
    Thus orig alcohol in A, Aaorig = 10oz, orig water in A, Aworig = 30oz
    Similarly, orig alcohol in B, Baorig = 4oz and Bworig = 36oz

    Now 8oz of A is transferred to B, this contains 2oz of Alcohol and 6oz of water
    Hence the new amount of alcohol in A is Aanew = 10-2 = 8oz, Awnew = 24oz
    the new amounts in B are Banew = 4+2 = 6, and Bwnew = 42oz
    The new concentration of alcohol in B is then 6oz in 48oz of solution

    Now 16oz of B is transferred, this contains 6oz*16/48 = 2oz alcohol and 14oz water
    The new value of Alcohol in A = Aanew + 2 = 10oz,new value of water in A = Awnew+14 = 38
    Thus the ratio of alcohol to water in A is 10oz : 38oz or, 5:19
    Hence C

    Whew!

  3. #3
    Trying to make mom and pop proud Bliss's Avatar
    Join Date
    Jan 2005
    Location
    Netherlands
    Posts
    29
    Rep Power
    16


    Good post? Yes | No

    Re: one of mixtures

    I got the same answer, C.

    It took me about five minutes to solve though... I used the same approach as Greycellz. Is there a shorter way to solve this problem?
    :: GMAT D-Day: April 22nd, 2005 ::

  4. #4
    Within my grasp!
    Join Date
    Dec 2004
    Location
    CT
    Posts
    398
    Rep Power
    17


    Good post? Yes | No

    Re: one of mixtures

    Agreed answer C. My question is how long did it take you guys to do this question? It took me about 4 solid minutes! Which is a lot if you get 3 questions like this in a row during your test!

  5. #5
    An Urch Guru Pundit Swami Sage prep2max's Avatar
    Join Date
    Feb 2005
    Posts
    524
    Rep Power
    18


    Good post? Yes | No

    Re: one of mixtures

    i think the following approach might save time

    A B
    al wt ttl al wt ttl
    org mix 10 30 40 4 36 40
    8 ounce of A is 1/5th of A
    stp1 -2 -6 32 +2 +6 48
    16 ounce of B is 1/3rd of B 8 24 6 42
    stp2 +2 +14 48 -2 -14 32
    NET 10 38
    10:38 = 5:19

  6. #6
    An Urch Guru Pundit Swami Sage prep2max's Avatar
    Join Date
    Feb 2005
    Posts
    524
    Rep Power
    18


    Good post? Yes | No

    Re: one of mixtures

    the spacing got lost when I posted the solution above, the point is to make vertical columns, to save time

  7. #7
    Trying to make mom and pop proud
    Join Date
    Mar 2005
    Posts
    5
    Rep Power
    16


    Good post? Yes | No

    Re: one of mixtures

    Quote Originally Posted by Bliss
    I got the same answer, C.

    It took me about five minutes to solve though... I used the same approach as Greycellz. Is there a shorter way to solve this problem?
    Put it in the form of a table and just add and substract on each side
    1-3 1-9
    10-30 4-36
    8- 24 6-42
    etc.

  8. #8
    Eager!
    Join Date
    Nov 2004
    Posts
    55
    Rep Power
    16


    Good post? Yes | No

    Re: one of mixtures


    Hear me through here for a second - In A we have a ratio of 1 to 3 or 25% alchohol. We take 8 ounces of it, meaning 2 ounces of alcohol and put it in B. B was 1 to 9 or 10% alcohol so it's original 40 contained 4 ounces of alcohol. after the addition of A we have 48 total ounces with 4+2 = 6 ounces of alcohol. Take 16 ounces of this , which will contain 2 ounces of alchol and add it back to A, which was 32 with 8 and now will be 10 ounes of alcohol out of 48 total ounces. So in fractional terms we're at 5/19. Is this the same as the ratio though? it seems like it would be 5 parts alcohol to 14 parts water???? Where am i screwing this up?

  9. #9
    An Urch Guru Pundit Swami Sage comp_bos's Avatar
    Join Date
    Nov 2004
    Location
    US
    Posts
    738
    Rep Power
    18


    Good post? Yes | No

    Re: one of mixtures

    Quote Originally Posted by jimmy slade

    Hear me through here for a second - In A we have a ratio of 1 to 3 or 25% alchohol. We take 8 ounces of it, meaning 2 ounces of alcohol and put it in B. B was 1 to 9 or 10% alcohol so it's original 40 contained 4 ounces of alcohol. after the addition of A we have 48 total ounces with 4+2 = 6 ounces of alcohol. Take 16 ounces of this , which will contain 2 ounces of alchol and add it back to A, which was 32 with 8 and now will be10 ounes of alcohol out of 48 total ounces. So in fractional terms we're at 5/19. Is this the same as the ratio though? it seems like it would be 5 parts alcohol to 14 parts water???? Where am i screwing this up?

    10 ounes of alcohol out of 48 total ounces
    Hence water = 48-10 = 38 ounces
    Hence Ratio of A:W = 10:38 = 5:19

  10. #10
    Eager!
    Join Date
    Nov 2004
    Posts
    55
    Rep Power
    16


    Good post? Yes | No

    Re: one of mixtures

    thank you, in my haste i said 10/48 = 5/19 not 5/24 which would be 5 to 19. duh. i like how this question makes you distinguish between ratios and fractions

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Mixtures
    By ibelieveican in forum GMAT Problem Solving
    Replies: 10
    Last Post: 09-12-2010, 10:46 AM
  2. Mixtures
    By vijay1311 in forum GMAT Problem Solving
    Replies: 6
    Last Post: 07-22-2010, 05:12 PM
  3. Mixtures
    By Ersandy in forum GMAT Problem Solving
    Replies: 5
    Last Post: 10-11-2008, 09:11 PM
  4. 21.21 mixtures
    By bmwhype in forum GMAT Problem Solving
    Replies: 2
    Last Post: 12-14-2007, 03:48 PM
  5. Mixtures
    By Malegria in forum GMAT Problem Solving
    Replies: 2
    Last Post: 10-04-2004, 03:19 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •