Aptitude - Clock - Discussion

5min = 30dg (degree).

1min = 6dg.

If min 6 dg = hr 1/2 dg.

So angle between hr and min hand is 6*30 = 180dg.

Now from 12, hr hand is shifted and we have to call that shift.

So from 12, min hand is 25 min.

So 25*1/2 = 17.5dg.

Now 180+17.5dg = 197.5dg.

Thnks rishi your explanation is very easy.

How to apply theta = 30h-(11/2)m in this question.

Can we apply those in every question?

Min hand take 60 min for complete 360 degree.

So 1 min = 360/60.
1 min = 6 degree.

Hour hand take 12 hours to complete 360 degree.

So 1 min = 360/ (60*12).
1 min = 0.5 degree.

So 8'o clk - 2'o clk = 6 hrs,

1 hour = 0.5*60 = 30 degree.
So 6 hour = 6*30 = 180 degree.

1 hour = 30 deg.

So, 8-2 = 6 hr.

6*30 = 180 deg.

In 12 min min hand takes 6 degree.

So for 6 hrs it takes ?

(6*60*6)/12 = (3600*6)/3 = 180 deg.

Explain every lines in detail:

In 60 minutes, the minute hand gains 55 minutes on the hour on the hour hand.

In every hour, both the hands coincide once.

The hands are in the same straight line when they are coincident or opposite to each other.

When the two hands are at right angles, they are 15 minute spaces apart.

When the hands are in opposite directions, they are 30 minute spaces apart.

Angle traced by hour hand in 12 hrs = 360°.

Angle traced by minute hand in 60 min. = 360°.

If a watch or a clock indicates 8.15, when the correct time is 8, it is said to be 15 minutes too fast.

On the other hand, if it indicates 7.45, when the correct time is 8, it is said to be 15 minutes too slow.

Simple method :

Total hours between 8 am to 2pm (H) = 6 hours (normal counting)
minutes (M)=0.

Use this formula {angle= [30*H - (11/2)*M] }.

Where H= hours, M= minutes. Put the values
Angle = 30*6 - (11/2)*0.
= 180-0 = 180 degrees.

P.S. If minutes are given put that value in same formula.

360°/12 = 30°.

8 to 2 o'clock = 6 hrs.

30° * 6 = 180°.

Angle = 60*h/2.

Where, h=hour.