Aptitude - Clock - Discussion

The best way to do is using this formulae 11/2m - 30h.

Kindly find my observation for the above question is.

I. Minute hand takes 5 minute that is 300 seconds to complete a 30* space
therefore in 1 sec; 1/10 degree space it covers.

II. Hour hand takes 60 minute that is 3600 seconds to complete a 30 degree space
therefore in 1 sec; it covers 1/120 degree space.

Therefore in 25 minutes,
minute hand rotates to 25x60x1/10 = 150 degree.
and hour hand moves to 25x60x1/120 = 17.5 degree.

ie., in 25 minutes from 10 o'clock; minute and hour hand forms an angle of 192.5 (150 + 30 +(30 - 17.5)) degree.

Therefore the reflex angle will be 167.5 degrees.

Please correct me if I am wrong.

The hour hand moves 1/2 degree every minute and 30 degrees each hour so after 10.25 the hour hand moves (10 * 30) + (25 * .5) = 312.5 degree.

Now the minute hand moves 6 degrees each minute so (6 * 25) = 150 degrees the reflex angle will be 360 - (312.5 - 150) = 197.5 degrees.

You cleared it all, Thanks @Hell Rider.

Well said @Shreekanth.

10 hr 25 min =10 * 60 min + 25 min = 625 min.

625 min = 625/60 hr = 125/12 hr.

We can use simple formula that,

Angle = 11%2 * min - (30 * hour).

ie) angle = 11%2 * 25 - (30 * 10).

So angle = 162.5.

To find the reflex angle, angle = 360 - 162.5.

= 197.5 degree.

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!

Answer to this and formula to this is as simple as this (360 - (30h - (11/2) * m) ) that's all.

For this question 360 - 162.5 = 197.5, as simple as that.

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?