Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Problem with maths question please help

  • 22-01-2012 6:35pm
    #1
    aarong1169
    Registered Users 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 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 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. :)


Advertisement