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Math Help - another word problem

  1. #1
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    Joined
    Feb 2008
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    5

    another word problem

    two planes start from the same airport and fly in opposite directions. the second plane starts 46 mins after the first, but its speed is 50mph faster. 2 hours and 15 mins after the first plane starts its flight the planes are 2325 miles apart. find the speed of each plane.
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  2. #2
    Newbie
    Joined
    Mar 2008
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    Ok, So here's how I did it, might not be the easiest way, but it get's her done!

    Imagine that the first plane is P1, the time of first plane is T1; speed is V1. Accordingly for the second plane it would be P2, T2, V2.

    P1 has a total time of 2.25 hrs.
    P2 has a total time of 2.25 hrs (135 mins) - 46 mins.. so 89 mins or 1.48hrs
    If we say that V1 is equal to X + 50 (because it is 50mph faster in this case), and V2 is equal to X then we can produce the following formula

    X + (X + 50) = 2325

    BUT! There is the time factor here. So we multiply these values by the appropriate T1 and T2

    2.25X + 1.48(X + 50) = 2325
    2.25X + 1.48X + 74 = 2325
    3.73X + 74 = 2325
    3.73X = 2251
    X = 603.485 mph
    V1 is equal to 603.485 mph
    V2 is equal to 603.485 mph + 50 mph = 653.485 mph

    To Verify:
    Multiply the V1 and V2 by the times to get
    (603.485)(2.25) + (653.485)(1.48)
    1357.841 + 967.158
    = 2324.999
    = 2325 miles

    Hope this is clear and helpful!
    Last edited by mrbuttersworth; April 16th 2008 at 01:53 PM.
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