Results 1 to 4 of 4

Math Help - DVT word problem help needed

  1. #1
    Newbie
    Joined
    Jan 2011
    Posts
    7

    Angry DVT word problem help needed

    A airplane that travels from one city to another city against the wind takes it 4 hours to get there, the voyage back only takes it 2 hours. If the distance between both city's is 600km, what is the speed of the plane?

    So far I have:


    D = V x T
    Go 600 4
    Return 600 2


    It's a table.

    So,

    600/4=V
    600/2=V

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

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Methodd View Post
    A airplane that travels from one city to another city against the wind takes it 4 hours to get there, the voyage back only takes it 2 hours. If the distance between both city's is 600km, what is the speed of the plane?

    So far I have:


    D = V x T
    Go 600 4
    Return 600 2


    It's a table.

    So,

    600/4=V
    600/2=V

    Is this right so far?
    600 = (v - u)(4) .... (1)

    600 = (v + u)(2) .... (2)

    Equate equations (1) and (2) and simplify: v = 3u.

    Substitute v = 3u into either equation (1) or (2) and solve for u. Therefore get v.

    I will let you think about which of u or v is the speed of the plane.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jan 2011
    Posts
    7
    Quote Originally Posted by mr fantastic View Post
    600 = (v - u)(4) .... (1)

    600 = (v + u)(2) .... (2)

    Equate equations (1) and (2) and simplify: v = 3u.

    Substitute v = 3u into either equation (1) or (2) and solve for u. Therefore get v.

    I will let you think about which of u or v is the speed of the plane.
    Ah yes, its coming back now. Thank you very much my good sir!
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,306
    Thanks
    1283
    Quote Originally Posted by Methodd View Post
    A airplane that travels from one city to another city against the wind takes it 4 hours to get there, the voyage back only takes it 2 hours. If the distance between both city's is 600km, what is the speed of the plane?

    So far I have:


    D = V x T
    Go 600 4
    Return 600 2


    It's a table.

    So,

    600/4=V
    600/2=V

    Is this right so far?
    Okay, so the net speed going (against the wind) was 600/4= 150 mph and returning (with the wind) was 600/2= 300 mph. Taking v to be "indicated air speed" (speed of the plane relative to the wind) and w to be the wind speed, we have v- w= 150 and v+ w= 300. Add those two equations to solve for v and subtract them to solve for w.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help with word problem needed.
    Posted in the Differential Equations Forum
    Replies: 2
    Last Post: November 25th 2010, 08:08 AM
  2. help needed on word problems (urgent)
    Posted in the Algebra Forum
    Replies: 1
    Last Post: February 24th 2010, 03:45 PM
  3. Help needed setting up a word problem
    Posted in the Statistics Forum
    Replies: 3
    Last Post: December 4th 2009, 03:45 PM
  4. Replies: 4
    Last Post: November 2nd 2009, 10:40 PM
  5. Word problem help needed!
    Posted in the Geometry Forum
    Replies: 2
    Last Post: February 6th 2006, 07:31 AM

Search Tags


/mathhelpforum @mathhelpforum