Roshan is proud of his swiss watch that he got as birthday gift from his father. Roshni like teasing her brother and on one occasion she said "what is there with a costly watch. The reflex angle between the hands are the same in yours and mine". If the time was 11:20, then what was the reflex angle?
Answers
Assume small hand of watch is on 11 and large hand is on 4 in a clock.
12 hour = 360°
1 hour = 360 / 12 = 30°
So, distance of hands from 11 to 4 is 5.
5 hours i.e. 30*5 = 150°
So, if small hand is on 11 and large is on 4, angle will be 150°
But small hand will not be exactly on 11 because 20 minutes have passed after 11.
Degree moved in 1 hour (60 minutes) = 30°
Therefore degrees moved in 20 minutes = 10°
So, net effect is 150° - 10° = 140°
Reflex angle = 360° - 140° = 220°
Hope this resolves your query. If you still have any doubts feel free to comment below.
Given:
Time = 11:20
To find:
The reflex angle.
Solution:
To calculate the degree,
1 hour = 360 / 12 = 30°
The gap between the two hands can be given by,
30 * 5 = 150°
As one is in 11 and the other in 4.
There will be a deviation in the hand at 11 because 20 minutes have passed after 11.
To measure the deviation,
Deviation in 60 minutes = 30°
Deviation in 20 minutes = 10°
So, the angle at 11:20 = 150 - 10 = 140°
Hence,
Reflex angle = 360° - the angle at 11:20
360° - 140° = 220°
If the time was 11:20, then the reflex angle = 220°