Aptitude - Clock - Discussion

In 3 min gain is 5 sec
so in 15 min gain is 25 sec
and in 60 min gain will be 100 sec
so in 9 hours and 15 min gain will be
925 sec i.e. 925/60 = 15 5/12
so correct ans is 3pm 59 7/12 min
Tell me whats wrong in my explanation ?

I have a different view for this question..
Its is straight from the question that the watch gains 1/12 min( 5 seconds) for every 3 min.
Den from 7 am to 4.15 PM its totally 555 min...

Now watch would have totally gained (1/12)*555/3= 15 5/12 min.
Therefore actual time would be (4.15 PM - 15 5/12 min) 3PM 59 7/12 min

In 3 MIN = The clock gains 5 sec.
in 60 min(3 * 20) = clock gains 100 sec(5 * 20)
= i.e 100/60 min
= 5/3 min
So , If correct clock shows 1 hour=den da wrong clock shows 1 hr 5/3 min..
i.e
1 hr=1 hr 5/3 min
=1 * 5/(3*60) hour (convert to hour)
=37/36 hour

But we need to do reverse..
i.e
37/36 hrs(in wrong clock) = 1 hr
1 hour in wrong clock = 1/(37/36)=36/37 hr

9hr 15min=37/4 hrs

So
37/4 hours in wrong clock =36/37 * 37/4
= 9
So 7 a.m + 9 hrs= 4 pm ....

I hope every1 got it...

How we got 4. 15 pm and 3 min. 5 sec. Of this clock = 3 min. Of the correct clock? Please I'm unable understand.

Thanks ya. This is very simple.

Thanks sundar! :) cheers :).

Thanks sundar. Done in a simple manner.

@Sundar:

Nice yaar :-)

To: Nitin

You are wrong. The given answer is correct. Don't get confused.

Let me explain in simple manner:

Error Clock :: Original Clock

3 min 5 sec :: 3 min

185 sec :: 180 sec

[9 hr 15 min = 555 min = 33300 sec]

33300 sec :: (180/185 x 33300) sec

33300 sec :: 32400 sec

333000sec = 9 hrs 15 min :: 32400 sec = 9 hrs [:. 32400/3600 = 9]

So,
Time passed by Error clock = 9 hrs 15 min.
Time passed by Original clock = 9 hrs.

Therefore, 9 hrs after 7 am is 4 pm.


Note: What was wrong in Nitin's explanation?

555/3 <--- Problem is here.

It should be

555 min/3 min 5 sec [or] 33300/185

Please think twice before solve problem. Hope this will help you. All the best!

NITIN CREATE CONFUSION