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 4 of 16.
Kiran said:
3 years ago
5sec gains in 3min.
5sec =3 min.
Multiply with 20.
100 sec gains in 60min(100sec = 60min).
Then 300sec = 180min.
Converting 300 sec into min is 5min.
180min is 3 hrs.
So it gains 5min in 3hrs.
We know that from 7 to 4 .15min is 9hrs 15min.
It gains 5min in 3hrs then for 9hrs it gains 15min so subtract 15 min from the time.
Then the answer is 4'pm.
5sec =3 min.
Multiply with 20.
100 sec gains in 60min(100sec = 60min).
Then 300sec = 180min.
Converting 300 sec into min is 5min.
180min is 3 hrs.
So it gains 5min in 3hrs.
We know that from 7 to 4 .15min is 9hrs 15min.
It gains 5min in 3hrs then for 9hrs it gains 15min so subtract 15 min from the time.
Then the answer is 4'pm.
(55)
Abhijit.K said:
1 decade 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.
Vivek said:
9 years ago
No Need to use such a long method.
In 3 mins it's gaining 5 sec.
Io in 1 min the gain take = 5/3.s
And in 60 min it's going to gain = (5/3) * 60= 100 s.
Now the difference between two times is 9 : 15 hrs.
And in 9 hrs it's going to gain 100 * 9 = 900 s.
900 /60 = 15 min.
So at 4 : 15 it's already 15 min ahead so real time will be 4.
In 3 mins it's gaining 5 sec.
Io in 1 min the gain take = 5/3.s
And in 60 min it's going to gain = (5/3) * 60= 100 s.
Now the difference between two times is 9 : 15 hrs.
And in 9 hrs it's going to gain 100 * 9 = 900 s.
900 /60 = 15 min.
So at 4 : 15 it's already 15 min ahead so real time will be 4.
Puppireddy Sai Krishna said:
3 years ago
If the clock gains 5sec for every 3mins it travels 9hrs and 15mins i.e., 9.25hrs.
Let the actual clock goes 'x' 3mins.
Then the clock which gains 5 secs for every 3 mins will go (3mins)x + (5secs)x =9.25hrs
=> (3+ (5/60))x = 9.25*60.
So x= 180mins,
i.e., x=3hrs,
So the actual clock goes 3x i.e., 9hrs.
So, 9hrs from 7 a.m. is 4 p.m.
Let the actual clock goes 'x' 3mins.
Then the clock which gains 5 secs for every 3 mins will go (3mins)x + (5secs)x =9.25hrs
=> (3+ (5/60))x = 9.25*60.
So x= 180mins,
i.e., x=3hrs,
So the actual clock goes 3x i.e., 9hrs.
So, 9hrs from 7 a.m. is 4 p.m.
(8)
Sonia said:
3 years ago
9 hr 15 min= 555min.
Watch gain 5 sec in 3 min so, we will check how many minutes gain 5 sec.
So, 555/3= 185min
185 min gains how many sec=185 multiplies with 5 = 925 sec.
And convert 925sec into min= 15.41 min( gain a minute, so we have to minus it from the time shown)
Now 4.15 was showing on the clock now minus 15min from it= 4pm.
Watch gain 5 sec in 3 min so, we will check how many minutes gain 5 sec.
So, 555/3= 185min
185 min gains how many sec=185 multiplies with 5 = 925 sec.
And convert 925sec into min= 15.41 min( gain a minute, so we have to minus it from the time shown)
Now 4.15 was showing on the clock now minus 15min from it= 4pm.
(79)
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)
Dedeepya said:
9 years ago
Can anyone tell me why can't we go with the below process?
For each 3 mins, it gains 5 secs.
So from 7 a.m to 4:15 pm it is 555 mins.
=> It gains 555*5/3 secs or (555*5)/(3*60) mins = 15.425 min.
i.e 15 + 5/12 mins.
So deducting this extra time from 4:15 pm we get 59'7/12 mins past 3.
Please, tell me where I am wrong.
For each 3 mins, it gains 5 secs.
So from 7 a.m to 4:15 pm it is 555 mins.
=> It gains 555*5/3 secs or (555*5)/(3*60) mins = 15.425 min.
i.e 15 + 5/12 mins.
So deducting this extra time from 4:15 pm we get 59'7/12 mins past 3.
Please, tell me where I am wrong.
Khairul Basar said:
1 year ago
Gain:
3 minutes 5 sec,
15 minutes 25 sec,
30 minutes 50 sec,
60 min( 1 hour) 100 sec.
Then, 7 to 4:15 - 9 hours 15 minutes.
Per hour 100 sec= 900.
And 15 minutes 25 sec.
Total - 925 sec.
925 sec รท 60 = 15 minutes.
(15 mins is extra).
9 hours 15 - 15 minutes 9 hours.
7 AM to 4 PM (9 hours).
So, the answer is 4 PM.
3 minutes 5 sec,
15 minutes 25 sec,
30 minutes 50 sec,
60 min( 1 hour) 100 sec.
Then, 7 to 4:15 - 9 hours 15 minutes.
Per hour 100 sec= 900.
And 15 minutes 25 sec.
Total - 925 sec.
925 sec รท 60 = 15 minutes.
(15 mins is extra).
9 hours 15 - 15 minutes 9 hours.
7 AM to 4 PM (9 hours).
So, the answer is 4 PM.
(74)
Deepak said:
1 decade ago
I have a different view for this question..
Its is straight from the question that the watch gains 1/12 min( 5 seconds) for every 3 min.
Den from 7 am to 4.15 PM its totally 555 min...
Now watch would have totally gained (1/12)*555/3= 15 5/12 min.
Therefore actual time would be (4.15 PM - 15 5/12 min) 3PM 59 7/12 min
Its is straight from the question that the watch gains 1/12 min( 5 seconds) for every 3 min.
Den from 7 am to 4.15 PM its totally 555 min...
Now watch would have totally gained (1/12)*555/3= 15 5/12 min.
Therefore actual time would be (4.15 PM - 15 5/12 min) 3PM 59 7/12 min
Shashi said:
6 years ago
We know that 9hr+15min, by converting it in min we get 540+15 = 555min-----eqn1.
To get 3 min parts, we divide 555/3 = 185.
Or we can say we have 185, 3 min.
Multiplying 185 * 5sec (by converting it into min ie 5/60) = 185* (5/60) = 15min.
So distracting 555min - 15min=540.
Or 4hr:15min - 15min = 4hr or 4o'clock.
To get 3 min parts, we divide 555/3 = 185.
Or we can say we have 185, 3 min.
Multiplying 185 * 5sec (by converting it into min ie 5/60) = 185* (5/60) = 15min.
So distracting 555min - 15min=540.
Or 4hr:15min - 15min = 4hr or 4o'clock.
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