Aptitude - Clock - Discussion

Keep it simple friends! Just use this formula.

12/11 (minutes to be gained). See in the question between 9 to 10'o clock we know that at 9:45 the hands will coincide so 45 minutes is to be gained from 9 o'clock.

So 12/11* (45) =49 1/9 (Answer).

Friends.

We know that the hour and the minute hand will coincide somewhere between 9 and 10. At 9:45, the angle between the hour & the minute hand is 22.5 degrees (the hour hand gains 0.5 degree per minute, i.e. 45/2 degrees in 45 mins).

Now, assume that the minute and the hour hand coincide at x mins after 9:45.

So, in x mins, the hour hand moves x/2 degrees while the minute hand moves 6x degrees.

So, 6x - x/2 = 22.5 (i.e. from the original position to the new position)

So, x = 45/11 = 4 1/11.

So, the time at their meeting is 49 1/11.

@Gaurav Mittal.

How you counted moves for minute hand ? i.e. You took 6x. How? Can you please explain?

What does this means 55 min. spaces gained in 60 min ? what does spaces here means?

Total distance the minute hand cover with respect to hour hand is 270'

And the relative speed is 5.5.

So the time to cover is,

270/5.5 = 540/11.

Can someone please explain me, what is the main concept used to solve this problem?

You can try this way also.

360 = 30(10)-(11/2)m.
360-300 = (11/2)m.
(60*2)/11 = m.
m = 120/11;

Now just do: 60-(120/11) = 540/11 = 49.1/11.

What master formula you are giving its not applicable to a single question we are doing. All the time its having negative sign error. I don't think so that is the master formula but can say this is confusing the whole concept we read till now.