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Are u good in math?

 
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Jan24-05, 11:14 AM   #1
 
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Are u good in math?


Hi

I just want to know in a clock, 12’O clock both needles (hour and minute) will coincide (one over the other)
My question is exactly at what time both needles will coincide again after 12’o clock

Good luck.
 
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Jan24-05, 11:16 AM   #2
 
13.05 ?
 
Jan24-05, 02:10 PM   #3
 
movement of hourhand:
hour hand moves 360 degree in 12 hours.
one hour is 30 degree. or 60 minutes =30 degree movement
6 minutes = 3 degrees
one minute= .5 degrees.
5 minutes =2.5 degrees

minute hand moves 360 degrees in 60 minutes
5 minutes = 30 degrees
one minute =6 degrees
at 1:05 the hour hand is at 32.5 degrees . minute hand is at 30 degrees
 
Jan24-05, 02:53 PM   #4
 
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Are u good in math?


Let [itex]\theta_h[/itex] be the angle of the hour hand away from the 12, and [itex]\theta_m[/itex] be the angle of the minute hand away from the 12. Then I think you can see that
[tex]12\,\theta_h=\theta_m+360^\circ n[/tex]
where n is an integer. Now set [itex]\theta_m=\theta_h[/itex] and solve for each n. For example, the first coincidence is at [itex]\theta_{h,m}=360^\circ/11[/itex], or 1:05:27.2727...
 
Jan25-05, 01:47 AM   #5
 
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Yes, but can you do it with hour, minute and second hands all coinciding? :-)
 
Jan25-05, 02:14 AM   #6
 
12:00
this is the only answer.....
 
Jan26-05, 01:42 AM   #7
 
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Can you prove it? :-)
 
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