In this post, I will give you the trick for solving Problems based on Clock. Before you start solving these problems, you must remember below given important points because they will be used.
- An accurate clock shows 8 o'clock in the morning. Through how many degrees will the hour hand rotate when the clock shows 2 o'clock in the afternoon?
(a) 144 (b)150
(c) 168 (d)180
Sol - 8 o'click in morning - 2 o'clock = 6 hours.
In 1 minute, an hour hand covers 1/2 degree and 1 hour = 60 minute. So, an hour hand will cover (1/2) x 60 = 30 degrees in 1 hour. In total, we have to find the degrees movement of an Hour clock in 6 hour so, it should be :
30 x 6= 180
(2) How many times are the hands of a clock at right angle in a day?
(a)22 (b) 24
(c)44 (d) 48
Sol - In 12 hours, they are at right angles 22 times so in 24 hours, they will at right angle at 44 times.
(3) How many times do the hands of a clock coincide in a day?
(a) 22 (b)24
(c) 44 (d) 48
Sol- Have a look on above show data, it is clearly written than hands of a clock overlap each other 22 times in a day so the answer will be 22.
(4) A clock is started at noon. By 10 minutes past 5, the hour hand has turned through:
(a) 145 degrees (b) 150 degrees
(c)155 degrees (d)160 degrees
Sol- 10 minutes past 5 means :: 5 : 10. It can also be said that it is 5 hours and 10 minutes.
For Minute Hand
(i) 1 min = 1/2 degree so 10 min = 5 degrees
(ii) 1 hour = 60 minute = 30 degree
(iii) 5 hour = 5 x 30 degree = 150 degree
But we have to find degree subtended by 5 Hours and 10 Minutes = 150 + 5 = 155 degrees
(5) The angle between the minute hand and the other hour hand of a clock when the time is 8:30 is
(a) 80 degrees (b) 75 degrees
(c) 60 degrees (d) 105 degrees
Sol - In this kind of question, use the formula which has been written above.
Degree required = (11/2) *30 - 30*8
= 15*11 - 240
= 75 degree
Note - Here please note that, you can get answer in negative form but never consider negative answer because it applies mod value.
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