Results 1 to 2 of 2

Math Help - Applications of Linear Systems

  1. #1
    Newbie
    Joined
    Feb 2009
    Posts
    17

    Lightbulb Applications of Linear Systems

    I need help understanding this problem:

    Tyrel and Dalia bought some pens and pencils. Tyrel bought 4 pens and 5 pencils, which cost him $6.71. Dalia bought 5 pens and 3 pencils, which cost her $7.12. Let a equal the price of a pen. Let b equal the price of a pencil.

    a.Write an equation that relates the number of pens and pencils Tyrel bought and the amount he paid for them.
    b.Write an equation that relates the number of pens and pencils Dalia bought and the amount she paid for them.
    c.Solve the systems you wrote for parts (a) and (b) to find the price of a pen and the price of a pencil.

    Thanks for helping!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    11
    Awards
    1
    Quote Originally Posted by amberkraidich View Post
    I need help understanding this problem:

    Tyrel and Dalia bought some pens and pencils. Tyrel bought 4 pens and 5 pencils, which cost him $6.71. Dalia bought 5 pens and 3 pencils, which cost her $7.12. Let a equal the price of a pen. Let b equal the price of a pencil.

    a.Write an equation that relates the number of pens and pencils Tyrel bought and the amount he paid for them.
    b.Write an equation that relates the number of pens and pencils Dalia bought and the amount she paid for them.
    c.Solve the systems you wrote for parts (a) and (b) to find the price of a pen and the price of a pencil.

    Thanks for helping!
    Hi amber,

    Let a = cost of each pen
    Let b = cost of each pencil

    a. 4a + 5b = 6.71

    b. 5a + 3b = 7.12

    c. Use elimination method to solve the system

    Multiply equation a by -3.
    Multiply equation b by 5.

    -12a - 15b = -20.13
    25a + 15b = 35.60
    ---------------------

    Add the two equations to get:

    13a = 15.47

    a= 1.19

    Substitute this value for a back into either equation to solve for b
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Systems of Equations Applications
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 4th 2011, 02:08 PM
  2. Replies: 2
    Last Post: October 8th 2010, 09:25 PM
  3. Applications of Systems of Linear Equations
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 22nd 2009, 09:38 PM
  4. Applications of Linear Systems
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 24th 2008, 09:36 AM
  5. Applications of Systems,
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 24th 2006, 09:41 PM

Search Tags


/mathhelpforum @mathhelpforum