Results 1 to 6 of 6

Math Help - Time algebraic question.

  1. #1
    Newbie
    Joined
    May 2011
    From
    Krypon
    Posts
    18
    Thanks
    1

    Lightbulb Time algebraic question.

    A boy travels a distance of 60km cycling at a speed of 20km per hour. If the boy stops for a 20 minute rest each half hour throughout the journey and he reaches his destination at 4pm.What time did the boy start his journey?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,326
    Thanks
    1298

    Re: Time algebraic question.

    Well, what have you done on this? How long would it take to go 60 km at 20 km/hr? How many "half hours" are there in that? So what total length of time did he spend resting?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Oct 2011
    Posts
    37

    Re: Time algebraic question.

    It isn't all that difficult if you think about it. HallsofIvy says it all but just as a little hint, you know that velocity=Distance/Time so Time=Distance/Speed. Put the numbers in and you get the total time. Then you can work out how many 30 minute intervals there are and add 20 mins for each of them. All you have to do then is to subract the time from 4pm to get the starting time.
    Hope it helps!
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Jan 2012
    Posts
    7

    Re: Time algebraic question.

    Quote Originally Posted by MathBond View Post
    A boy travels a distance of 60km cycling at a speed of 20km per hour. If the boy stops for a 20 minute rest each half hour throughout the journey and he reaches his destination at 4pm.What time did the boy start his journey?
    Here we go.

    Distance = D = 60km
    Rate = R = 20km per hour

    Every 30 minutes, the boy travels 10km. [If he travels 20km per hour, half of that is 10km.]
    This means, the boy must make 6 bike trips of 30 minutes. This also means, there are 5 breaks in-between of 20 minutes.
    His trip looked like.. 30 bike, 20 rest, 30 bike, 20 rest, 30 bike, 20 rest, 30 bike, 20 rest, 30 bike, 20 rest, 30 bike.
    Of.. he biked 6 times, rested 5 times.
    6 x 30 = 180 minutes.
    5 x 20 = 100 minutes.
    His journey was for 380 minutes.

    380 minutes / (1 hour/60 minutes) = X ammount of hours.
    You take this number subtract by 4 pm and you have your answer.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jan 2012
    Posts
    9

    Re: Time algebraic question.

    Quote Originally Posted by okokjae View Post
    6 x 30 = 180 minutes.
    5 x 20 = 100 minutes.
    His journey was for 380 minutes.
    I would double-check your math if I were you.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    May 2011
    From
    Krypon
    Posts
    18
    Thanks
    1

    Re: Time algebraic question.

    Thanks.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Algebraic question
    Posted in the Algebra Forum
    Replies: 3
    Last Post: December 17th 2009, 04:02 AM
  2. an algebraic question
    Posted in the Algebra Forum
    Replies: 4
    Last Post: December 6th 2009, 06:14 AM
  3. Algebraic Fraction question...
    Posted in the Algebra Forum
    Replies: 2
    Last Post: February 14th 2009, 03:52 AM
  4. algebraic fraction question HELP!!!
    Posted in the Algebra Forum
    Replies: 5
    Last Post: January 5th 2008, 04:30 PM
  5. algebraic question
    Posted in the Algebra Forum
    Replies: 4
    Last Post: July 30th 2005, 10:07 PM

/mathhelpforum @mathhelpforum