Aptitude - Clock - Discussion
Discussion Forum : Clock - General Questions (Q.No. 5)
5.
How much does a watch lose per day, if its hands coincide every 64 minutes?
Answer: Option
Explanation:
55 min. spaces are covered in 60 min.
| 60 min. spaces are covered in |  |
60 | x 60 |  min. |
= 65 | 5 | min. |
| 55 | 11 |
| Loss in 64 min. = | |
65 | 5 | - 64 | |
= | 16 | min. |
| 11 | 11 |
| Loss in 24 hrs = | |
16 | x | 1 | x 24 x 60 | min. |
= | 32 | 8 | min. |
| 11 | 64 | 11 |
Discussion:
119 comments Page 3 of 12.
Arjun Mandavkar said:
4 years ago
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.
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.
(17)
Sachin said:
1 decade ago
First consider in how many minutes, hands should coincide.
55 min. spaces are covered in 60 min.
60 min. spaces will be covered in, 65 (5/11) i.e. 65.45 minutes.
But this clock is taking 64 minutes to coincide hence it is 1.45 min slow to actual time (65.45-64=1.45).
In 64 min of journey clock is 1.45 min slow, then
in 24*60 min it will 32.62 min slow.
=(24*60*1.45*1)/64= 32.62 or 32(8/11).
55 min. spaces are covered in 60 min.
60 min. spaces will be covered in, 65 (5/11) i.e. 65.45 minutes.
But this clock is taking 64 minutes to coincide hence it is 1.45 min slow to actual time (65.45-64=1.45).
In 64 min of journey clock is 1.45 min slow, then
in 24*60 min it will 32.62 min slow.
=(24*60*1.45*1)/64= 32.62 or 32(8/11).
Anand S Moghe said:
9 years ago
I have a small correction to offer to my previous explanation.
In 64 mins of correct time, the watch shows to have covered 65.5/11 mins. So the watch runs faster. Hence the time is gained. In 64 mins the time gained is 1.5/11 min. So in 24 hrs (1440 mins) the time gained is 1440*(16/11)*(1/64) = 32.8/11 mins.
So the time is GAINED, not lost, as per my understanding.
In 64 mins of correct time, the watch shows to have covered 65.5/11 mins. So the watch runs faster. Hence the time is gained. In 64 mins the time gained is 1.5/11 min. So in 24 hrs (1440 mins) the time gained is 1440*(16/11)*(1/64) = 32.8/11 mins.
So the time is GAINED, not lost, as per my understanding.
(1)
Karan singh saud said:
9 years ago
Very simple question.
A clock coincides 11 times in 12 hrs (720 min).
So, per meeting =720/11 (65.45).
i.e hands coincide after every 65.45 min.
But according to the question. Hands coincide every 64 min.
So clock losses 1.45 min for every meeting.
And we know that hands coincide 22 times a day.
So. Answer = 22 * 1.45. (I guess this is correct).
A clock coincides 11 times in 12 hrs (720 min).
So, per meeting =720/11 (65.45).
i.e hands coincide after every 65.45 min.
But according to the question. Hands coincide every 64 min.
So clock losses 1.45 min for every meeting.
And we know that hands coincide 22 times a day.
So. Answer = 22 * 1.45. (I guess this is correct).
(1)
Harish Udupa s said:
9 years ago
Hands coincide every 65 min 27 secs (google it for proof) but here it happens every 64 min.
So it runs behind by 1 min 27s so for every 65 min 27 secs (3927s) there's delay of 1 min 27s (87).
Hence, for 24 hrs (86400s) there will be 87 * 86400/3927 = 1914.1329s = 31.90221 min, that's roughly 31 9/10min.
These type of questions won't be asked anyway.
So it runs behind by 1 min 27s so for every 65 min 27 secs (3927s) there's delay of 1 min 27s (87).
Hence, for 24 hrs (86400s) there will be 87 * 86400/3927 = 1914.1329s = 31.90221 min, that's roughly 31 9/10min.
These type of questions won't be asked anyway.
Aks said:
9 years ago
WHETHER THE CLOCK HAS GAINED OR LOST TIME?
We know from the calculation above that the two hands of the clock coincide every 65.45 mins.
But here it is mentioned that they meet every 64mins in the defective clock.
=> the clock is going fast.
=> in 24 hours it would be actually showing more than 24hours.
=> the clock has gained time!
We know from the calculation above that the two hands of the clock coincide every 65.45 mins.
But here it is mentioned that they meet every 64mins in the defective clock.
=> the clock is going fast.
=> in 24 hours it would be actually showing more than 24hours.
=> the clock has gained time!
Manasa said:
1 month ago
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.
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.
(8)
Prasanth said:
1 decade ago
What does "55 min spaces" mean? I can't get it. I understand the clock concept like this.
-->Hour hand covers 0.5 degree in 1 min.
-->Min hand covers 6 degrees in 1 min.
-->Sec hand covers 360 degrees in 1 min.
And I used to solve all problems using this theory. But I can't get this min spaces concept. Some one help me.
-->Hour hand covers 0.5 degree in 1 min.
-->Min hand covers 6 degrees in 1 min.
-->Sec hand covers 360 degrees in 1 min.
And I used to solve all problems using this theory. But I can't get this min spaces concept. Some one help me.
SMZ said:
8 years ago
As per the given question the clock is not losing the time, where as it is gaining the time.
Actual clock coincide for every 65 5/11min where as this faulty clock coinciding for every 64th min. That means this clock is running faster than the actual clock so the answer comes exactly 32min not 32 8/11min.
Actual clock coincide for every 65 5/11min where as this faulty clock coinciding for every 64th min. That means this clock is running faster than the actual clock so the answer comes exactly 32min not 32 8/11min.
Shahaji said:
6 years ago
Actual time of overtake/coincide = 65 5/11 min.
False clock overtakes/ coincide = 64 min.
For every 65 5/11 min of actual time false watch gains 1 5/11 min= 16/11 min time.
therefore in a day that is 24 hrs time gained will be;
65 (5/11)/24 = 1 (5/11)/x.
x = 32 minutes gain in 1 day.
False clock overtakes/ coincide = 64 min.
For every 65 5/11 min of actual time false watch gains 1 5/11 min= 16/11 min time.
therefore in a day that is 24 hrs time gained will be;
65 (5/11)/24 = 1 (5/11)/x.
x = 32 minutes gain in 1 day.
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