Results 1 to 3 of 3

Math Help - Help check please

  1. #1
    Junior Member
    Joined
    Jun 2005
    Posts
    58

    Question Help check please

    Suppose y varies inversely as x and y =24 when x= 3. Find x when y = 36.

    So I worked it out I got this:

    36 -24 = x - 3
    12+3 = 15
    15 =x

    y=36 , x=15

    Is this right?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Apr 2005
    Posts
    1,631
    "y varies inversely as x "

    y ----> 1/x
    y = k(1/x) ----the equation.

    y=24 when x=3, so,
    24 = k(1/3)
    24 = k/3
    24*3 = k
    k = 72

    Hence, when y = 36,
    36 = 72(1/x)
    36 = 72/x
    36x = 72
    x = 72/36 = 2 ---answer.

    --------------
    Another meaning of "y varies inversely as x" is:
    if x goes higher, then y goes lower; if x goes lower, then y goes higher...proportionately.
    Last edited by ticbol; July 3rd 2005 at 12:46 PM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jun 2005
    Posts
    58
    thank you
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: March 12th 2011, 04:05 AM
  2. Check this pls
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 31st 2010, 01:23 PM
  3. can some one check this for me?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: August 9th 2009, 09:24 AM
  4. Somebody check if this is ok!
    Posted in the Calculus Forum
    Replies: 5
    Last Post: June 16th 2008, 09:02 AM
  5. Check IVP
    Posted in the Calculus Forum
    Replies: 14
    Last Post: September 12th 2007, 11:33 AM

Search Tags


/mathhelpforum @mathhelpforum