Results 1 to 5 of 5

Math Help - Algebra word problem

  1. #1
    Newbie
    Joined
    Dec 2012
    From
    Massachusetts
    Posts
    2

    Algebra word problem

    A chemist ran out of a 72 ml solution of 12% alcohol. All that is left in the lab is 8% alcohol and 20% alcohol. How many ml of 8% and 20% would be needed to make a 72 ml solution of 12%?

    This is what I have so far.


    .12 X 72=8.64

    .08x + .2y=8.64

    (100) .08x + .2y=8.64 (100)

    8x + 20y= 864


    Any help in solving it would be appreciated. I am at a dead end.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Junior Member
    Joined
    Nov 2012
    From
    Abu Dhabi
    Posts
    55
    Thanks
    3

    Re: Algebra word problem

    Shouldn't x and y be equal to 72 ?

    you can then make 2 equation, the one that you did
    and x+y = 72
    and solve them..
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Dec 2012
    From
    Massachusetts
    Posts
    2

    Re: Algebra word problem

    Do you mean x + y =72

    The whole point is to find a solution using 8% and 20% alcohol.

    You are probably a lot better at this than I am.
    How could I set that up?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Nov 2012
    From
    Abu Dhabi
    Posts
    55
    Thanks
    3

    Re: Algebra word problem

    You have 2 unknowns and 2 equations..
    x+y =72
    2x+ 5y =216

    solve them and find x and y

    ((you chose x to be the volume of the 8% solution
    and y for the 20% solution))
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Super Member
    Joined
    Nov 2007
    From
    Trumbull Ct
    Posts
    910
    Thanks
    27

    Re: Algebra word problem

    let x= ml of 20% alc to be added to (72-x ) ml of 8% alc to make 72 ml of 12%alc
    write an alc balance
    0.2 x +(72-x)*0.08 = 0.12*72
    x=24 72-x = 48
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Algebra 2 Word Problem #2
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 2nd 2009, 02:48 PM
  2. Algebra 2 word problem
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 2nd 2009, 02:37 PM
  3. algebra word problem
    Posted in the Algebra Forum
    Replies: 3
    Last Post: December 13th 2008, 08:48 AM
  4. Algebra word problem
    Posted in the Algebra Forum
    Replies: 1
    Last Post: September 22nd 2008, 03:19 PM
  5. Algebra Word Problem
    Posted in the Algebra Forum
    Replies: 7
    Last Post: January 21st 2008, 10:48 PM

Search Tags


/mathhelpforum @mathhelpforum