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 3 of 16.
Pooja said:
1 decade ago
From 7 am to 4 pm, We are getting 900 sec gain, which is 900/60 = 15 min gain.
Now, the question has asked what will be the actual time when it is showing 4:15 pm.
Now, at 4 pm it already has gained 15 min, i.e. it is showing 4:15 pm already.
I was doing it wrong when I took 900 + 25 sec, where 25 sec was for 4 to 4:15 pm, which is wrong.
We are not asked to calculate time at 4:15 pm, we are asked for 4 pm.
Now, the question has asked what will be the actual time when it is showing 4:15 pm.
Now, at 4 pm it already has gained 15 min, i.e. it is showing 4:15 pm already.
I was doing it wrong when I took 900 + 25 sec, where 25 sec was for 4 to 4:15 pm, which is wrong.
We are not asked to calculate time at 4:15 pm, we are asked for 4 pm.
(1)
Yamini Dhanasekar said:
7 years ago
We can also solve it by;
Time from 7 a.m to 4.15 pm is 9hrs and 15 mins.
9hrs is 540 min and 15 min=555 min.
Then, how many 3 min in 555 min=555/3=185.
So, 5 sec is added 185 times.
185*5=925 sec.925 sec can be converted into 15 min(925/60=15.4 @approx 15min).
Watch shows the time at 4:15 pm.
15 min added.so the correct time is 4 PM.
Time from 7 a.m to 4.15 pm is 9hrs and 15 mins.
9hrs is 540 min and 15 min=555 min.
Then, how many 3 min in 555 min=555/3=185.
So, 5 sec is added 185 times.
185*5=925 sec.925 sec can be converted into 15 min(925/60=15.4 @approx 15min).
Watch shows the time at 4:15 pm.
15 min added.so the correct time is 4 PM.
(1)
Jaslin said:
2 decades ago
How we got 37/720 ?
Khalid said:
2 decades ago
For 9 hrs the clock gains 15 min. Then what about the remaining 15 min in the quarter past 4. ? can't understand. ?
Bala said:
1 decade ago
Hai Jaslin,
To convert mins and secs into hrs we do:
(3/60)+(5/(60*60)) = 185/3600 = 37/720.
I think u might be clear of this.
To convert mins and secs into hrs we do:
(3/60)+(5/(60*60)) = 185/3600 = 37/720.
I think u might be clear of this.
Saranya said:
1 decade ago
How did you get 185 ?
Swetha said:
1 decade ago
Can anybody tell me how did we get '1/20 hrs of the correct clock' ?
Ajay said:
1 decade ago
@Swetha
3 min converted into hours by dividing with 60.
3/60 hrs = 1/20 hrs.
3 min converted into hours by dividing with 60.
3/60 hrs = 1/20 hrs.
Nitesh Nandwana said:
1 decade ago
@Saranya
(3/60)+(5/(60*60)) = 185/3600 = 37/720.
185, it is simple calculation babes.
(3/60)+(5/(60*60)) = 185/3600 = 37/720.
185, it is simple calculation babes.
Vinu said:
1 decade ago
Any body understand last step? can you explain?
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