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Maths problem

Discussion in 'Mathematics' started by georgina2010, Jan 20, 2012.

  1. A year 10 Unit 2 higher exam question (grade a) from Edexcel: just after one o'clock the hour and minute hand are pointing in the same direction meaning that the angle between them is 0. What time is this to the nearest second?
    This comes as a review question from the topic of angles, polygons and circles.
     
  2. A year 10 Unit 2 higher exam question (grade a) from Edexcel: just after one o'clock the hour and minute hand are pointing in the same direction meaning that the angle between them is 0. What time is this to the nearest second?
    This comes as a review question from the topic of angles, polygons and circles.
     
  3. 1:05:27
     
  4. We have the answer, we are not sure that our method is the easiest way of doing it though! Any suggestions?
     
  5. PaulDG

    PaulDG Occasional commenter

    http://wiki.answers.com/Q/What_times_on_a_clock_form_a_straight_line
     
  6. It happens every 12/11 hours. I think it's easiest to get it by thinking about a twelve hour period. How many times does it happen? How long must the intervals between be?
     
  7. The minute hand moves at 6 degrees per minute, the hour one at 0.5.
    if 1 o clock is time zero, then at t minutes later the minute hand would be at 6t, the hour hand at 30+0.5t (30 degrees since it starts off pointing at the 1 and 0.5t for the increase per minute). They both pass when
    6t=30+0.5t
    which gives t=5.454545.
    so 5 mins 27 secs past one.
     
  8. Thanks for the help!
     
  9. DeborahCarol

    DeborahCarol New commenter

    Blimey, does anyone else think this is a bit tough for Year 10 Higher? Or is it just my cold tonight? Someone make me feel better. Please. (About the question, not the cold.)
     
  10. I think that's tricky too! Good job I've seen it on here...
    PS here's a [​IMG] for your cold!
     
  11. DeborahCarol

    DeborahCarol New commenter

    Thank you! Suspect I'm not the only one who's printed out the thread!
     
  12. Was this question from an actual exam paper? Or just from some revision material provided by the board. I agree that it is a very difficult question if it was from an actual exam but does provide a good discussion when revising angles with high ability students.
     

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