Aptitude - Clock - Discussion

Total minutes per day: 24 x 60 = 1440.

Minute and hour hands coincide 22 times per day so, 1440/22 = 720/11 = 65 5/11.

Here in question, it coincides every 64 mins.
So, loss in every coincide is;
65 5/11 - 64 = 16/11 or 1 5/11.

Therefore,
Loss per every coincide x number of coincide per day = total loss per day.
So, 16/11 x 22 = 32 mins per day.


@All
Please, anyone, explain me why divided by 64 and multiply by 24 and 60.

The difference between time is 4min here.
Between 60 and 64 min, and I'd we take;
4min × 24 = 96, 96 is now common between.
60 and 64 min like 4 min, we need to find the difference for 64 min, so;
(64/24) × 96 = 256 =>32/11×8.

@Dawa Tshering.

Total minutes per day: 24 x 60 = 1440.

Minute and hour hands coincide 22 times per day so, 1440/22.
= 720/11,
= 65 5/11.

Here in question, it coincides every 64 mins.
So, loss in every coincide is;
65 5/11 - 64 = 16/11 or 1 5/11.

Till this you are correct!

However the no of coincidence per day is 22 for a normal clock.
In this peculiar clock, the coincidence happens every 64 mins.
Therefore, in 24 hours the no of coincidence is ( 24*60)/64 which is 22.5.
That means in 24 hours, this peculiar clock coincides 22.5 times.

Now, going by your logic,
Loss per every coincide x number of coincide per day = total loss.
So, 16/11 x 22.5 = 32 8/11 mins per day.

Agree @Abdeali Chitalwala.

You are absolutely right.

@All.

Since the Normal clock coincides after every 65.45 min. But in question, it is given that hands coincide after 64 mins. Hence, the clock is gaining time.

The speed is inversely proportional to time, if clock hands are fast they lose time and when clock hands are slow they gain time.

If the clock covers 60-minute spaces in 64 minutes instead of 65+ (5/11) then the clock is faster, hence losing time. (taking less time than actual time).

I think it's 90 min.

One day = 24 hours = 1440 minutes.
Hands meet every 65.5 minutes,
Number of times they meet = 1440 ÷ 65.5 ≈ 22 times.
Real clock: 65.5 minutes.
Your watch: 64 minutes.
Difference = 65.5 − 64 = 1.5 minutes per meeting.
Number of meetings × difference per meeting = 22 × 1.5 = 33 minutes.
Your watch loses about 32-33 minutes in one day.

The answer is 32 mins.
Hands of a clock coincide at every 65. 5/11 mins.
In a day hands of a clock coincide 22 times.
if it coincides at every 64 minutes,it gains 1.5/11 mins,
So in a day it gains 22 *1.5/11 = 32 minutes.