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:
120 comments Page 9 of 12.
Girish said:
1 decade ago
I can't understand 65 5/11 how 5/11 is anybody explain?
Aum Jena said:
1 decade ago
Can anyone make me explain the last step?
Sagnik Chatterjee said:
1 decade ago
Can anyone make me understand this?
Debdeep said:
1 decade ago
Exactly @Vijendar.
I doubt in that point too. But it take me quite time.
Also the statement would be I think: "Gain in 65*5/11 is 16/11 min".
I doubt in that point too. But it take me quite time.
Also the statement would be I think: "Gain in 65*5/11 is 16/11 min".
Vijender said:
1 decade ago
This question is wrong. If the hands coincide every 64 minutes, then it should be a gaining clock. So how could a gaining clock lose time?
Vijender said:
1 decade ago
@Harish.
To find mirror image of a given time, there are two approaches, one is to draw the clock on paper indicating the time given and then find the mirror image of the hour hand and minute hand.
This is time consuming. The other method requires you only to subtract the given time from 12:00, and result will be your answer.
For the example you've given 8:40.
Subtract it from 12:00, we'll have 3:20 which is the right answer.
To find mirror image of a given time, there are two approaches, one is to draw the clock on paper indicating the time given and then find the mirror image of the hour hand and minute hand.
This is time consuming. The other method requires you only to subtract the given time from 12:00, and result will be your answer.
For the example you've given 8:40.
Subtract it from 12:00, we'll have 3:20 which is the right answer.
Vivek g shivhare said:
1 decade ago
This some's difficulty is bit high, that's why here we have to consider relative speeds of hands of clock. Not separate got it?
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.
Apurba said:
1 decade ago
How can coincide 24 times in a day, any one can explain? I think it may coincide 23 times in a day, but only meet 24 times in a day.
Shivangi said:
1 decade ago
The universal rule is , hands of any accurate clock meets after 65 5/11 [=(11*65+5)/11] minutes.
But here the clock is taking 64 minutes to meet !
Hence , the error is [65 5/11]-[64] mints -> 16/11 minutes .
Now , total minutes in a day is = 24 hrs* 60 minutes= 1440 minutes.
Now, we know , the error in 64 mins was --> 16/11.
Means in 1 min ---> 16/11*1/64.
So in 11440 mins---> (16/11*1/64)*11440.
Which equals to ---> 360/11 Answer.
But here the clock is taking 64 minutes to meet !
Hence , the error is [65 5/11]-[64] mints -> 16/11 minutes .
Now , total minutes in a day is = 24 hrs* 60 minutes= 1440 minutes.
Now, we know , the error in 64 mins was --> 16/11.
Means in 1 min ---> 16/11*1/64.
So in 11440 mins---> (16/11*1/64)*11440.
Which equals to ---> 360/11 Answer.
(1)
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