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:
157 comments Page 12 of 16.
Banu said:
1 decade ago
What is mean by "when the watch indicated quarter past 4 o'clock"?
B Rajesh Kannan said:
1 decade ago
Dear Asha,
The clock set right at 7.00 am but thereafter it gains 5 seconds every 3 minutes, hence we have to calculate the correct time.
The clock set right at 7.00 am but thereafter it gains 5 seconds every 3 minutes, hence we have to calculate the correct time.
Asharani.k said:
1 decade ago
@Asha.
Given that the "clock was set right at 7:00am". So, I think there is no error in time further. Hence at 4:00pm the time is 4:00pm itself.
Please suggest me if I'm wrong.
Given that the "clock was set right at 7:00am". So, I think there is no error in time further. Hence at 4:00pm the time is 4:00pm itself.
Please suggest me if I'm wrong.
Azar said:
1 decade ago
Time from 7 a.m to 4:15 p.m = 9hr 15min. Please explain the above line. how to get the answer "9 hrs 15 min"?
Kakoli said:
1 decade ago
But it is stated in the question that the wrong clock gains 5 sec in 3 mint. Does it mean that it is 3 mint 5 secs fast?
I'm confused. Someone please explain it for me.
I'm confused. Someone please explain it for me.
Vivek said:
1 decade ago
Time from 7 a.m to 4:15 p.m = 9hr 15min.
= 9*60min+15min = 555min.
3min 5sec clock(wrong) = 3min (correct).
3*60sec+5sec = 3*60 sec.
185sec = 180sec.
If 1 sec = 180/185 sec.
Then 555 min = (180/185)*555.
= 540 min.
= 9hr.
Than correct answer is 7a.m +9hr = 4p.m.
= 9*60min+15min = 555min.
3min 5sec clock(wrong) = 3min (correct).
3*60sec+5sec = 3*60 sec.
185sec = 180sec.
If 1 sec = 180/185 sec.
Then 555 min = (180/185)*555.
= 540 min.
= 9hr.
Than correct answer is 7a.m +9hr = 4p.m.
(1)
Soujanya said:
1 decade ago
Can anyone tell the reason behind the multiplication [1/20*720/37*37/4]?
(1)
Soujanya said:
1 decade ago
Why they are multiplying the values at last to get 9 hrs? I am confused here. Rest all is clear. Please help me.
(1)
Anusha said:
1 decade ago
Still I'm confused how the 37/720 hrs is equal to 1/20 hrs.
Praveen said:
1 decade ago
FAULT CLOCK CORRECT CLOCK
7am < ---------------- > 7am
8am 100 sec < ------------ > 8am
9am 200 sec < ------------ > 9am
So on..
4pm 900 sec < ------------ > 4pm
So 4pm 900 sec = 4pm 900/60 min = 4pm 15 min.
Therefore when Fault clock shows the time 4pm 15 min the Correct clock will show 4pm.
So correct answer is 4pm.
7am < ---------------- > 7am
8am 100 sec < ------------ > 8am
9am 200 sec < ------------ > 9am
So on..
4pm 900 sec < ------------ > 4pm
So 4pm 900 sec = 4pm 900/60 min = 4pm 15 min.
Therefore when Fault clock shows the time 4pm 15 min the Correct clock will show 4pm.
So correct answer is 4pm.
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