Aptitude - Clock - Discussion
Discussion Forum : Clock - General Questions (Q.No. 4)
4.
A watch which gains 5 seconds in 3 minutes was set right at 7 a.m. In the afternoon of the same day, when the watch indicated quarter past 4 o'clock, the true time is:
Answer: Option
Explanation:
| Time from 7 a.m. to 4.15 p.m. = 9 hrs 15 min. = | 37 | hrs. |
| 4 |
3 min. 5 sec. of this clock = 3 min. of the correct clock.
 |
37 | hrs of this clock = | 1 | hrs of the correct clock. |
| 720 | 20 |
| |
37 | hrs of this clock = |  |
1 | x | 720 | x | 37 |  |
hrs of the correct clock. |
| 4 | 20 | 37 | 4 |
= 9 hrs of the correct clock.
The correct time is 9 hrs after 7 a.m. i.e., 4 p.m.
Discussion:
154 comments Page 9 of 16.
Vivek said:
1 decade ago
Correct answer is (A).
In 3 min fast is - 5 sec.
In 1 min fast is - 5/3 sec.
In 60 min fast is - 5/3*60 - 100 sec.
So 1 hr fast is - 100 sec.
In 9 hr 25 sec - 925 sec.
Si actually fast is - 900 sec + 25 sec = 900/60+25/60 = 15 5/12 min.
So actual time is = 3 hr 59*7/12.
In 3 min fast is - 5 sec.
In 1 min fast is - 5/3 sec.
In 60 min fast is - 5/3*60 - 100 sec.
So 1 hr fast is - 100 sec.
In 9 hr 25 sec - 925 sec.
Si actually fast is - 900 sec + 25 sec = 900/60+25/60 = 15 5/12 min.
So actual time is = 3 hr 59*7/12.
Kasinath@Hyd said:
1 decade ago
7am to 4:15====>is 9hrs and 15 min.
3min ====EXCEEDS===> 5sec.
15min==============> 25sec equation (1).
1hr (60min) =========> 100sec.
====================
======So on=========
====================
9hr=================> 900sec equation (2).
9:15 == equation(1)+equation(2) => 925 sec i.e. in 9:15 min time exceeded by 15 min.
Therefore time is 4 pm and not 4:15.
3min ====EXCEEDS===> 5sec.
15min==============> 25sec equation (1).
1hr (60min) =========> 100sec.
====================
======So on=========
====================
9hr=================> 900sec equation (2).
9:15 == equation(1)+equation(2) => 925 sec i.e. in 9:15 min time exceeded by 15 min.
Therefore time is 4 pm and not 4:15.
Sachin said:
10 years ago
A clock is showing 14:19, what will time after 14399999991 min.
Akhil Sunder said:
10 years ago
How 37/720 is changed to 720/37?
SHILPA said:
10 years ago
Can't understand why 3 min 5 sec corrected to 3:00 min?
Abhijit.K said:
10 years ago
In 3 mins clock gains 5 sec.
15 mins -- -- 25 sec.
6o mins --- ----- 100 sec.
Now, from 7 am to 4:15 pm total time = 9 hrs 15 mins.
So, in 9 hrs clock gains = 9*100 = 900 sec.
In 15 mins -- --- = 25 sec.
Therefore, total gain by the clock in these 9 hrs 15 mins = (900/60+25/60) = 15 min 5/12 sec.
Hence correct time will be 59*7/12 min past 3.
15 mins -- -- 25 sec.
6o mins --- ----- 100 sec.
Now, from 7 am to 4:15 pm total time = 9 hrs 15 mins.
So, in 9 hrs clock gains = 9*100 = 900 sec.
In 15 mins -- --- = 25 sec.
Therefore, total gain by the clock in these 9 hrs 15 mins = (900/60+25/60) = 15 min 5/12 sec.
Hence correct time will be 59*7/12 min past 3.
Sai Charan Reddy said:
10 years ago
I think the correct option is A. From 7 am to 4:15 pm, number of minutes passed is 555 min. As given for every 3 min it gains an extra 3 seconds.
So 555/3 = 185 min. Therefore 185*(5/60) = 15*5/12, so subtract 4:15 with 15*5/12, we get 59*7/12 min past 3.
So 555/3 = 185 min. Therefore 185*(5/60) = 15*5/12, so subtract 4:15 with 15*5/12, we get 59*7/12 min past 3.
Anandkumar.A said:
10 years ago
Hi guys anyone explain about the (3/60) + (5/(60*60)) = 185/3600 = 37/720. Calculation please.
Sai Sowmya said:
10 years ago
@Anandkumar.
Calculation is simple.
3/60 = 1/20.
5/60*60 = 5/3600 = 1/720.
Now add both the values ==> 1/20+1/720 = 37/720.
Calculation is simple.
3/60 = 1/20.
5/60*60 = 5/3600 = 1/720.
Now add both the values ==> 1/20+1/720 = 37/720.
Dhanababu said:
9 years ago
Hai friends,
I think we have to find the error.
Clock gains 5 sec in 180sec of actual clock.
So,
The error is 5 sec in 185 sec. in errored clock.
In error clock. The passed time is 9H and 15min.
Which is equal to 555 min.(9 * 60 + 15).
Thus it is 33300 in sec.
We have 5 sec error for every 185 sec.
So for 33300 sec we have 900 sec error. (33300 * 5/185).
Error in min. is 15 (900 sec / 60).
So the actual time is 4:00pm (4:15 - 15 min).
I hope you all understood.
I think we have to find the error.
Clock gains 5 sec in 180sec of actual clock.
So,
The error is 5 sec in 185 sec. in errored clock.
In error clock. The passed time is 9H and 15min.
Which is equal to 555 min.(9 * 60 + 15).
Thus it is 33300 in sec.
We have 5 sec error for every 185 sec.
So for 33300 sec we have 900 sec error. (33300 * 5/185).
Error in min. is 15 (900 sec / 60).
So the actual time is 4:00pm (4:15 - 15 min).
I hope you all understood.
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