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Thread: heh heh need help in Pri 4 maths....

  1. #1
    Moderator ed9119's Avatar
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    Default heh heh need help in Pri 4 maths....

    been trying to figure this one out for the last few hours without success..... google here and there also no help...... been a long week and brain is fried from work..... so I'm mathematically challenged tonight ha ha

    I'm almost a nervous wreck and brain cannot take this torture any more......

    There were 3 alarm clocks in the room.
    The 1st clock beeps every 12 mins
    The 2nd clock beeps every 8 mins
    The 3rd clock beeps every 6 mins
    If they first beeped together at 7am, what time would they beep together again ?



    If u know how to get the answer show the workings too ha ha ha
    Last edited by ed9119; 23rd April 2010 at 10:42 PM.
    shaddap and just shoot .... up close
    Walkeast

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    Default Re: heh heh need help in Pri 4 maths....

    7:24am?

    1st clock: 7:00, 7:12, 7:24
    2nd clock: 7:00, 7:08, 7:16, 7:24
    3rd clock: 7:00, 7:06, 7:12, 7:18, 7:24

    to solve it mathematically, just find the lowest common multiple of the three intervals.

    or is there a trick somewhere? hahaha

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    Default Re: heh heh need help in Pri 4 maths....

    Oh... LCM question...

    Here goes:
    LCM of 12, 8, 6 = 24

    Therefore, if starting time is 7am, the next time they beep together will be 7.24 am.

    Cheers!

    LCM is Lowest Common Multiple.

    Multiple of 12 is 12, 24, ...
    Multiple of 8 is 8, 16, 24, ...
    Multiple of 6 is 6, 12, 18, 24, ...

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    Senior Member madmartian's Avatar
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    Default Re: heh heh need help in Pri 4 maths....

    My brain just stalled looking at this
    Take the shot!

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    Moderator ed9119's Avatar
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    Default Re: heh heh need help in Pri 4 maths....

    i worked on the 2 min interval between the 6min beep and 8min beep clocks and 4 min interval between the 8min beep and the 12min beep clocks

    got to 60min and 120mins and dunno if ans should be 9am ?
    shaddap and just shoot .... up close
    Walkeast

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    Moderator ed9119's Avatar
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    Default Re: heh heh need help in Pri 4 maths....

    Quote Originally Posted by zapline View Post
    Oh... LCM question...

    Here goes:
    LCM of 12, 8, 6 = 24

    Therefore, if starting time is 7am, the next time they beep together will be 7.24 am.

    Cheers!

    LCM is Lowest Common Multiple.

    Multiple of 12 is 12, 24, ...
    Multiple of 8 is 8, 16, 24, ...
    Multiple of 6 is 6, 12, 18, 24, ...
    7am, 7.06am, 7.18am, 7.24am
    7am, 7.08am, 7.16am, 7.24am
    7am, 7.12am, 7.24am

    oh yah hor !!!!! wah lau....... no wonder my 9 year old laughing at me all night

    ok thread closed !!!
    shaddap and just shoot .... up close
    Walkeast

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