Aptitude - Clock - Discussion
Discussion Forum : Clock - General Questions (Q.No. 2)
2.
The reflex angle between the hands of a clock at 10.25 is:
Answer: Option
Explanation:
| Angle traced by hour hand in | 125 | hrs = |  |
360 | x | 125 |  |
° | = 312 | 1 | ° | . |
| 12 | 12 | 12 | 2 |
| Angle traced by minute hand in 25 min = | |
360 | x 25 | |
° | = 150°. |
| 60 |
 Reflex angle = 360° - |
|
312 | 1 | - 150 | |
° | = 360° - 162 | 1 | ° | = 197 | 1° | . |
| 2 | 2 | 2 |
Discussion:
269 comments Page 4 of 27.
Prasad said:
1 decade ago
Minute hand moves 6 degree in a minute
Hour hand moves 1/2 degree in a minute
At 10:25, the minute hand is at 5 and hour hand is at 10 the difference between them is 35minute space
there degree is 35*6 = 210,
but hour hand is not exactly at 10 because it has moved to the extent of 25 minutes.
so it has moved to the degree of 25*1/2 = 12.5
reflex degree of 10:25 = 210 - 12.5
= 197.5
Hour hand moves 1/2 degree in a minute
At 10:25, the minute hand is at 5 and hour hand is at 10 the difference between them is 35minute space
there degree is 35*6 = 210,
but hour hand is not exactly at 10 because it has moved to the extent of 25 minutes.
so it has moved to the degree of 25*1/2 = 12.5
reflex degree of 10:25 = 210 - 12.5
= 197.5
A.Margaret said:
8 years ago
The angle b/w 10 & 5(10:25) is 150.
For 25 min,hr hand moves 12.5 degrees.the actual angle now is 150+12.5=162.5.To calculate reflex angle 360-162.5=197.5
For simple understanding,let's assume the time is now 12.we can say the angle b/w hr hand & min hand is 0 or 360(reflex angle). At 1'o clock the angle is 30 or 330(reflex).likewise at 10:25 the angle is 162.5 or 197.5.
For 25 min,hr hand moves 12.5 degrees.the actual angle now is 150+12.5=162.5.To calculate reflex angle 360-162.5=197.5
For simple understanding,let's assume the time is now 12.we can say the angle b/w hr hand & min hand is 0 or 360(reflex angle). At 1'o clock the angle is 30 or 330(reflex).likewise at 10:25 the angle is 162.5 or 197.5.
Praveen said:
3 years ago
Step1. find angle b/w 12 and minute hand. ( ie, 150 °)
Step2. find angle b/w hour hand and 12,
Step3. Add angles.
* In 1 hr the hour hand moves 30 degree --> ( 60 * 30 )/60,
*from 10 to 12 --> 60 degree.
In 25 minutes hour hand moves 25 * 30 / 60 degree --> 12.5 degree.
Angle b/w hour hand and 12 is--> 60 - 12.5 = 47.5 degree.
47.5 + 150 = 197.5 degree.
Step2. find angle b/w hour hand and 12,
Step3. Add angles.
* In 1 hr the hour hand moves 30 degree --> ( 60 * 30 )/60,
*from 10 to 12 --> 60 degree.
In 25 minutes hour hand moves 25 * 30 / 60 degree --> 12.5 degree.
Angle b/w hour hand and 12 is--> 60 - 12.5 = 47.5 degree.
47.5 + 150 = 197.5 degree.
(8)
Abhitha said:
7 years ago
First, we have to calculate the angle between hour and minute hand.
Time given=10.25.
Angle between two hand=(30*H)-11/2*M.
=(30*10)-11/2*25,
=300-137.5,
=162.5.
Reflex angle = 360-162.5.
=197.5 ie;197 1/2.
Time given=10.25.
Angle between two hand=(30*H)-11/2*M.
=(30*10)-11/2*25,
=300-137.5,
=162.5.
Reflex angle = 360-162.5.
=197.5 ie;197 1/2.
Keerthana said:
9 years ago
At 10.25, if the hour hand would stay at 10, the angle between hour and min hands would be 180°. But because it moves, the angle by which the hour hand would've deviated from 10 in 25 mins would be;
60 : 30 :: 25 : x (In one hour the hour hand moves by 30°)
x = 12.5°
So, 180 + 12.5 = 192.5°.
Can somebody please tell me where I am going wrong?
60 : 30 :: 25 : x (In one hour the hour hand moves by 30°)
x = 12.5°
So, 180 + 12.5 = 192.5°.
Can somebody please tell me where I am going wrong?
Shez said:
10 years ago
At 10 o'clock angle between them = 300.
For 25 min displacement between them = 25*5.5 = 137.5.
So, angle between them = 300-137.5 = 162.5.
For reflex angle = 360-162.5 = 197.5.
OR 30H - (11/2) M.
H----Hours.
M----Minutes.
So, substitute 30(10) - (11/2)(25).
= (300-137.5) = 162.5.
If the angle is < 180 sub from 360 viceversa.
= 360-162.5 = 197.5.
For 25 min displacement between them = 25*5.5 = 137.5.
So, angle between them = 300-137.5 = 162.5.
For reflex angle = 360-162.5 = 197.5.
OR 30H - (11/2) M.
H----Hours.
M----Minutes.
So, substitute 30(10) - (11/2)(25).
= (300-137.5) = 162.5.
If the angle is < 180 sub from 360 viceversa.
= 360-162.5 = 197.5.
Nirmal Saxena said:
9 years ago
The above problem are solved by the bellow formula.
Angle between X and Y = |(X * 30) - ((Y * 11)/2)|.
Angle between hands at 10 : 25.
Step 1: X = 10, Y = 25.
Step 2: 10 * 30 = 300.
Step 3: (25 * 11)/2 = 137.5.
Step 4: 300 - 137.5 = 162.5.
Thus, angle between hands at 10:25 is 162.5 degrees.
Now reflex:
360 - 162.5.
197.5 is the answer.
Thankyou!
Angle between X and Y = |(X * 30) - ((Y * 11)/2)|.
Angle between hands at 10 : 25.
Step 1: X = 10, Y = 25.
Step 2: 10 * 30 = 300.
Step 3: (25 * 11)/2 = 137.5.
Step 4: 300 - 137.5 = 162.5.
Thus, angle between hands at 10:25 is 162.5 degrees.
Now reflex:
360 - 162.5.
197.5 is the answer.
Thankyou!
Malli Reddy said:
10 years ago
In general the reflex angle b/n hours hand at 10 and minutes hand at 25 is 210.
But movement of min hand by 25 causes hours hand to move.
12.5 degrees forward (reason:for every min min hand moves 6 degrees causing hours hand 1/2 degree if you don't know this have a clear idea about clocks).
So, subtract 12.5 from 210.
210-12.5 = 197.5.
That's it.
But movement of min hand by 25 causes hours hand to move.
12.5 degrees forward (reason:for every min min hand moves 6 degrees causing hours hand 1/2 degree if you don't know this have a clear idea about clocks).
So, subtract 12.5 from 210.
210-12.5 = 197.5.
That's it.
Sahithi said:
3 years ago
1hr---> 30°
Then 8hr --->240°
As we know 60min --->30° than for 25 min ---> 12.5.
Now, 8hr25min forms --->240+12.5=252.4,
as the minute hand is at 5 then the angle of the minute hand becomes 5*30=150,
Now the angle b/w the hands will become 262.5-150=102.5,
But the question is about the reflex angle.so,360-102.5= 197.5.
Then 8hr --->240°
As we know 60min --->30° than for 25 min ---> 12.5.
Now, 8hr25min forms --->240+12.5=252.4,
as the minute hand is at 5 then the angle of the minute hand becomes 5*30=150,
Now the angle b/w the hands will become 262.5-150=102.5,
But the question is about the reflex angle.so,360-102.5= 197.5.
(33)
Durga said:
1 decade ago
Here we have given 10.25
=>the hour hand will rotate 10 hrs and 25 minute
But we know that 60minute =1hr
so 1min=1/60hrs
25 min=25/60=5/12 hrs.........................................(1)
the hour hand covered 10 hrs and 25 minute
So total hour covered=
10+5/12 hrs {from equation 1}
=(120+5)/12
=125/12
=>the hour hand will rotate 10 hrs and 25 minute
But we know that 60minute =1hr
so 1min=1/60hrs
25 min=25/60=5/12 hrs.........................................(1)
the hour hand covered 10 hrs and 25 minute
So total hour covered=
10+5/12 hrs {from equation 1}
=(120+5)/12
=125/12
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