Aptitude - Clock - Discussion

The two hands of a clock coincide after a gap of every 65 5/11 minutes.

For example, if we consider the starting time at 12 . the two hands coincide exactly at 12. Again after 65 5/11 minutes both coincide. Means exactly at 1 5/11 minutes.

In the problem, the two hands of a clock coincide after 64 minutes give.

It means the clock is faster than usual. It means it is gaining time.

For Every 64 minutes the clock gains 65 5/11- 64 = 1 5/11 = 16/11 minutes.

It GAINS not Loses.

So in the problem, for 64 mints clock gains ( faster) 16/11 minutes.

Then it gains how much per day? ( for 24*60 hrs)

Answer = {24*60 *16/11 }/64.

= 32 8/11 mints.

You explanation is nice. Thank you @Konxie.

As per the formula, it is;

((720/11) -64) * ( (60*24) /64).

How to get 1.5/11 from 16/11? Please explain.

The clock is GAINING 1 and 5/11 mins every hour and not losing.

There's an error in the question.

Hence, the clock will GAIN 32 and 8/11 mins in one day.

Thanks for explaining @Maddy.

Hello @Konxie,

Why to find loss per minute? Can't we just multiply with 24?
Like, 1.45* 24...

Please tell me.

It's a proven fact that for a normal clock after every 720/11 = 65.4545 minutes both minute and hour hand meet.

In this case, the hour and minute hands are meeting after every 64 minutes which is less than 65.4545.

This clearly indicates the clock is going faster.

For every hour the clock is gaining 720/11 - 64 = 16/11 = 1.4545 minutes.

Hence, for 24 hours it will gain 24 * 16/11 = 34.909 = 34 10/11.

Well explained & very simple. Thanks @Shivangi.

How 1/64? Please explain.