Aptitude - Clock - Discussion

@Nitin

Initially, it is 2 min low at 12 pm so to compensate that loss 2min gain is there but at last, why do they calculate for 2 min gain individually? Explain it.

@All.

Gaining always count from the correct time. 4min gain from correct time but the clock is late by 2min also, therefore, we must include the time (from -2min to correct time) and then add 4 min to them.

2 min late means that at some point it will show correct time and then after that it gains 4 min 48 sec. So total gain= 2min to correct time to 4 min 48 sec i.e. 2+4min48sec.

(2 min + 4 min 48 seconds)=(408 seconds).

For 170 hours.

For 1 hr (408/170)=2.4 seconds,
For 120 seconds(2 min initially),
Hours=(120/2.4)=50.

So Wednesday 2 PM.

Finally, I satisfied with the answers of @Akash vashista and Shashank. Thanks, both of them.

How we are getting after calculation 4min 48 sec in denominator i.e. (5?).

I understood 4*60=240 but I am not getting that how 5 came in the denominator.

Please, anyone help me. Thanks.

The answer is 2 AM, not 2PM.

The minute hand of a clock overtakes the hour hand at intervals of 65 minutes of the correct time. How much a day does the clock gain or loss? Can anyone answer this?

2 mins are lost in begin but gradually as it is gaining 4 min and 48 sec, so in between, it might be on correct time at the instance,

So we do first check how much it gains, i.e

Time from 12 p.m. on Monday to 2 p.m. on the following Monday = 7 days 2 hours = 170 hours.

The watch gains
2 + 4 (4/5) min. or 34/5 min. in 170 hrs.

Now, 34/5 min. are gained in 170 hrs.

2 min. is gained in (170 x5/34x 2) hrs = 50 hrs. [This is which we lost in the beginning of the clock , as we lost 2 mins so we calculated how much it will take to recover]

It is 2:00 PM on Tuesday
----------------------------------------------

A watch gains uniformly is 2 min slow at 12:00 on Sunday.

On the following Sunday, it is 4 min 48 sec fast at 2 PM.

Total time between 12 AM and 2 PM on another sunday
= (24*7) + 2 hours.
= 170 hour.

Time gained = 4 min 48 sec + 2 min.
= 6 min 48 sec.
= 408 sec.

The clock will show the correct time only when it gains 2 min;

408 sec ----> in 170 hours.
120 sec ---> in x hour.
408/170 = 120/x.
x = 50 hours.
= 2 days 2 hours for noon on the Sunday.