The hands of a clock coincide 11 times in every 12 hours (Since between 11 and 1, they
coincide only once, i.e., at 12 o'clock).
The hands overlap about every 65 minutes, not every 60 minutes.
The hands coincide 22 times in a day.
On straight line means 180 degree angle.
180 = 11/2 min ? 30 hrs
180 = 11/2 m ? 30 × 3
180 = 11/2 m ? 90
(180 + 90) 2 = 11 m
m = 540/11 = 49 1/11 minutes.
For ticking 6 times, there are 5 intervals.
Each interval has time duration of 30/5 = 6 secs
At 12 o'clock, there are 11 intervals,
so total time for 11 intervals = 11 x 6 = 66 secs.
Angle between hands of a clock
When the minute hand is behind the hour hand, the angle between the two hands at M minutes past H 'o clock
=> degrees
Here H = 4, M = 15 and the minute hand is behind the hour hand.
Hence the angle
= 30[4-(15/5)]+15/2 = 30(1)+7.5 = 37.5 degrees
Coincide means 00 angle.
This can be calculated using the formulafor time A to B means [11m/2 - 30 (A)]
Here m gives minutes after A the both hands coincides.
Here A = 3, B = 4
0 =11m/2 ?30 × 3
11m = 90 × 2 = 180
m= 180/11 = 16 4/11
So time = 3 : 16 4/11
Minute hand covers 5400/60 = 90°
point to be remembered
Angle traced by hour hand in hrs = =
Angle traced by min. hand in 20 min = =
Required angle = (130 - 120)º = 10º
We know that the time difference between India and USA is 9 hrs 30 min.
India is 9:30 hrs ahead of USA.
Time in India = 4:15 + 9:30 = 13:45 PM.
Required Time after 18 hrs = 13:45 + 18 hrs = 7:45 AM.
Hence it is 7:45 AM on the next morning.
At 3 o'clock, the minute hand is 15 min. spaces apart from the hour hand.
To be coincident, it must gain 15 min. spaces.
55 min. are gained in 60 min.
Then 15 min spaces are gained in = min.
Therefore, The hands are coincident at min. past 3 o'clock.
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