Results 1 to 2 of 2

Math Help - Algebra word problem

  1. #1
    Newbie
    Joined
    Dec 2008
    Posts
    17

    Algebra word problem

    A pollution control device reduces the rate of emission of an air pollutant in a car's exhaust by 56 parts per million per hour. When the device is installed, it will take the car 10 hr to emit the same amount of pollutant that it formerly did in 3 hr. What was the original rate of emission of the pollutant in the car's exhaust ?

    Thank you.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,824
    Thanks
    713
    Hello, sahip!

    A pollution control device reduces the rate of emission of an air pollutant
    . . in a car's exhaust by 56 parts per million per hour.
    When the device is installed, it will take the car 10 hr to emit the same amount
    . . of pollutant that it formerly did in 3 hr.

    What was the original rate of emission of the pollutant in the car's exhaust?

    Let ppm = parts per million.

    Let x ppm/hr = engine's original rate of emission of pollutant.

    In 3 hours, it emits 3x ppm of pollutant.


    With the device installed, the engine's rate is: x-56 ppm/hr

    In 10 hours, it emits 10(x-56) ppm of pollutant.


    These two amounts are equal: . 10(x-56) \:=\:3x

    . . 10x - 560 \:=\:3x \quad\Rightarrow\quad 7x \:=\:560 \quad\Rightarrow\quad x \:=\:80


    Therefore, the original rate of pollutant emission is 80 ppm/hr.

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. help with algebra word problem
    Posted in the Algebra Forum
    Replies: 1
    Last Post: September 25th 2011, 02:08 PM
  2. Algebra 2 Word Problem #2
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 2nd 2009, 02:48 PM
  3. Algebra word problem
    Posted in the Algebra Forum
    Replies: 1
    Last Post: September 22nd 2008, 03:57 PM
  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: 1
    Last Post: May 6th 2008, 12:59 PM

Search Tags


/mathhelpforum @mathhelpforum