Aptitude - Clock - Discussion

Gains uniformly is 2 minutes low. means clock is 2 min late at noon on Monday.

Now on next Monday it is 4 min 48 sec fast means it total gain is,
= ( 2 min + 4min 48sec).
The time total gain is (2+4min 48sec)i.e 2*60+4*60+48=408 Sec.
means 408 sec covered in 170 hrs (from this Monday to fallowing Monday means 7 * 24 = 168hrs + from 12.00pm to 2.00pm means 2hrs, i.e 168+2=170hrs),
In 1hrs 85/204 sec covered (170/408).
So to cover 120 sec (2mns)how many hours taken.

=(85/204)*120,
=50 hrs.

To cover 2mns it takes 50hrs. so it will show correct time on 2 days 2 hrs after (2*24+2=50)i.e Wednesday 2.00 PM.

Gain means the clock's hands are moving fast than actual time (i.e it takes less than 60minutes for minute's hand to complete 360 degrees).

Initially, the time in given clock is 11:58am but the actual time is 12 pm (this might be because someone changed the time to 11:58 in given clock).

Since the clock is moving fast it's time is 4min 48sec fast on following Monday. Now at one point in between present Monday to next Monday the given clock's time coincides with normal clock's time (i.e correct time). Now total time from 12 pm to next Monday 2pm is 170hours. Total time gain by given clock = 2+ (4min 48sec) = 34/5min in 170 hours. What we need now is 'When it shows the correct time. ' If clock gains those 2minutes which it is lagging initially then it shows the correct time. 34/5min gain in 170hours then 2min will gain in 170*2* (5/34) hours.

Thank you all for the given explanation.

Sam sets alarm at 5 am. But the clock loses 16 minutes in 24 hours. Effectively, the clock indicates 10:00 pm on the 4th day. Find out the original time of the clock.

Tell me the answer for this question.

Very helpful. Thanks a lot @Akash.

@Piyush,

It's unitary method.
34/5 mins are gained in 170 hrs.
So 1 min is gained in 170 * 5/34 hrs.
So 2 mins are gained in 170 * 5/34 * 2 hrs.

2 min are gained in.

170 x (5/34) x 2 hrs = 50 hrs.

Can you please explain this.

Actually, my question is why we have multiplied "2" here?

Did'nt get it, please explain it once more and elaborate it.

We added 2 min to 4 min and 48 sec because the word gain was specified.

What can B the variation in question that will make us subtract 2 min from 4 min and 48 sec?

Thank you, @Akash.