Results 1 to 7 of 7

Math Help - Help with formulas?

  1. #1
    Newbie
    Joined
    Sep 2009
    Posts
    3

    Help with formulas?

    Would someone please explain to me how to solve these? I'm completely lost and can't even figure out one of the problems on my homework. I would greatly appreciate step-by-step instructions that are as non-confusing as possible.

    A=115+1/2(p+s) solve for s=?

    P=2w+2l solve for w=?

    Also, this word problem:
    Set up an equation for the given application problem.
    The perimeter of standard - size copier papper is 99 cm. The width is 6.3 cm less than the length. Find the length and the width.

    If you would like to just do one that's fine, I'm just in desperate need of some instructions.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member elninio's Avatar
    Joined
    Sep 2009
    Posts
    92
    Awards
    1
    Your first question is strange. I suppose its not looking for a concrete answer. in the first case, just isolate s to one side.
    A-115-1/2p=1/2s
    2A-230-p=s

    Try this for the second one.

    The perimeter of standard - size copier papper is 99 cm. The width is 6.3 cm less than the length. Find the length and the width.
    Let x be length and y be width.

    Perimeter = x+y+x+y = 2x+2y
    99=2x+2y

    y=x-6.3

    Substituting, we get...

    99=2x+2(x-6.3)
    99=4x-12.6
    111.6=4x
    x=27.9cm
    We know y is 6.3 less than this so,
    y=21.6cm
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    May 2009
    From
    New Delhi
    Posts
    153
    Sol. 1)
      \  a= 115 + \frac{1}{2} (p+s)
     \ a-15 = \frac{1}{2} (p+s) \ or  \  \frac{1}{2} (p+s) =\ a-15
     p+s =2(a-15)
     s =2(a-15) -p
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    May 2009
    From
    New Delhi
    Posts
    153
    sol. 2)
     P=2w+2l
     P-2l=2w
     2w=P-2l
     w=\frac{1}{2}(P-2l)
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member elninio's Avatar
    Joined
    Sep 2009
    Posts
    92
    Awards
    1
    Ramiee, In sol 1, 15 should be replaced by 115.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    May 2009
    From
    New Delhi
    Posts
    153
    oops
    Follow Math Help Forum on Facebook and Google+

  7. #7
    MHF Contributor
    Joined
    Dec 2007
    From
    Ottawa, Canada
    Posts
    3,160
    Thanks
    70
    A = 115 + 1/2(p + s)

    Don't wait; get rid of fraction RIGHT AWAY; multiply by 2:
    2A = 230 + p + s

    s = 2A - 230 - p

    Easier, right?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. I need formulas.....
    Posted in the Business Math Forum
    Replies: 7
    Last Post: August 24th 2009, 05:06 PM
  2. formulas help
    Posted in the Calculus Forum
    Replies: 0
    Last Post: October 20th 2008, 04:39 PM
  3. not sure about a few formulas?
    Posted in the Algebra Forum
    Replies: 3
    Last Post: January 27th 2008, 09:56 PM
  4. Using sin,cos,tan formulas.
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: March 15th 2007, 03:03 PM
  5. Formulas
    Posted in the Algebra Forum
    Replies: 3
    Last Post: April 28th 2005, 09:02 AM

Search Tags


/mathhelpforum @mathhelpforum