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Problem with maths question please help

  • 22-01-2012 05:35PM
    #1
    aarong1169
    Registered Users, Registered Users 2 Posts: 39 ✭


    could anyone please help me to do the following question? if you could explain too that would be good :)

    a jogger and a walker both cover a distance of 5km. the runner is travelling 1.5 times faster than the walker and finishes in 25 minutes less time. how fast is each going in km/hr?


Comments

  • #2
    smurphy11
    Users Awaiting Email Confirmation Posts: 93 ✭✭smurphy11


    aarong1169 wrote: »
    could anyone please help me to do the following question? if you could explain too that would be good :)

    a jogger and a walker both cover a distance of 5km. the runner is travelling 1.5 times faster than the walker and finishes in 25 minutes less time. how fast is each going in km/hr?

    ok so the runner takes 75 mins while the walker takes 50 mins so time for both

    distance
    =speed so it 5km divided by 5/6s for walker and 1.25 for runner
    time


  • #3
    aarong1169
    Registered Users, Registered Users 2 Posts: 39 ✭aarong1169


    smurphy11 wrote: »
    ok so the runner takes 75 mins while the walker takes 50 mins so time for both

    distance
    =speed so it 5km divided by 5/6s for walker and 1.25 for runner
    time
    wait where did you get 75 and 50 from.


  • #4
    Neodymium
    Registered Users, Registered Users 2 Posts: 179 ✭✭Neodymium


    I'm not sure if I've made a mistake but here goes ....

    Assign a variable to the speed and the time time for the walker and the runner, converting the time from minutes to hours.

    walker time = x hours
    runner time = (x -5/12) hours
    //25 minutes = 5/12 hours

    walker speed = y km/h
    runner speed = 1.5y km/h

    Speed = Distance ÷ Time

    Walker: y = 5/x

    Runner: 1.5y = 5/(x - 5/12)
    y = 5/(1.5)(x - 5/12)


    // Put the values of y together .....

    5/x = 5/(1.5)(x - 5/12)
    x = 1.25 hours
    // didn't show working out for clarity


    Walker: y = 5/x
    y = 5/1.25
    y = 4 km/h

    Runner: y = 4(1.5)
    y = 6 km/h
    // since runner is 1.5 times faster than the walker.


    Walker = 4 km/h
    Runner = 6 km/h




    I hope I'm right :confused:, if I'm wrong - sorry. :)


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