Aptitude - Clock - Discussion

30H-(11/2)M where H----Hours
M----Minutes..

How do you use this formula to calculate the angle when the clock is showing 3:25?

The below angles are defined

Acute angle Less than 90°
Right angle Exactly 90°
Obtuse angle Between 90° and 180°

Straight angle Exactly 180°
Reflex angle Between 180° and 360°
Full angle Exactly 360°

Vasuroshan answer is very simple and well undestandable but please tel me one thing if the angle is graterthan 180 then what we should do?

Minute hand speed= 6degree/min
thus in 25 minute= 6*25= 150 degree
hour hand speed = 1/2 degree/min
thus in 25 minute= 1/2 * 25= 12.5 degree
thus angle between these two hands= 150+12.5= 162.5 degree
thus reflex anlge= 360-162.5= 197.5 degree

@ Shreekanth. Thank you.

In reflex formula how you get 11/2? Please tell me.

Reflex angle means angle more than 180 but less than 360 . So, we should calculate larger angle not smaller angle betwn the hands . We can choose the angle between the hands in two ways one more than 180 and other less than 180(obtuse) .

10.25 hr =10hr + 25min = 10hr + 25/60hr = 125/12 hr

So, the angle movie by hr hand from 0 hr point(12 in our watch) is

360/12 * 125/12 = 312.5

Angle move my minute hand from 0 hr point is 360/60 * 25 = 150

So the smaller angle(obtuse) between the hands is 312.5 - 150 = 162.5

So the larger i.e. reflex angle = 360-162.5 = 197.5

Hai guys u can solve any problem regarding clocks easily by using formula
angle=(11/2)m-30h

Simply substitute minutes in place of 'm' and hours in place of 'h'.

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

I didn't get simplified formula to understand this problem so please help me by simple method.