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:
156 comments Page 8 of 16.
Khanam said:
10 years ago
Please explain me in clear and easy form I didn't understand this.
Omi said:
10 years ago
Wrong answer. The correct answer will be A.
7 am to 4:15 pm = 9h 15 minutes.
3 minutes -----> 5 seconds gains.
60 minutes -----> 100 seconds gains.
So, 9h + 15 minutes -----> 9 * 100,
= 900 seconds + (15/3) * 5 = 925 seconds gains.
So, 925 secs = 185/12 minutes.
So, the answer is A.
7 am to 4:15 pm = 9h 15 minutes.
3 minutes -----> 5 seconds gains.
60 minutes -----> 100 seconds gains.
So, 9h + 15 minutes -----> 9 * 100,
= 900 seconds + (15/3) * 5 = 925 seconds gains.
So, 925 secs = 185/12 minutes.
So, the answer is A.
Shivanand sattikar said:
10 years ago
@Praveen.
You gave an easy and best explanation, thanks man.
You gave an easy and best explanation, thanks man.
Jeyam said:
10 years ago
@Aishwarya.
You don't get confused, first calculate how many minutes are there.
9hrs * 60 minutes +15 = 555 minutes.
Again calculate how many 3 minutes are there i.e. 555 ÷ 3 =183.
Again 180 minutes * 5 second = 915.
Again 914 ÷ 60 = 15 minutes. So 4 : 15 - 15 = 4pm.
Don't bother about the remaining 15 sec because we calculate ahead of the 15 minutes, so it's very factual to deduct.
You don't get confused, first calculate how many minutes are there.
9hrs * 60 minutes +15 = 555 minutes.
Again calculate how many 3 minutes are there i.e. 555 ÷ 3 =183.
Again 180 minutes * 5 second = 915.
Again 914 ÷ 60 = 15 minutes. So 4 : 15 - 15 = 4pm.
Don't bother about the remaining 15 sec because we calculate ahead of the 15 minutes, so it's very factual to deduct.
Aishwarya said:
1 decade ago
Can any one explain this answer step by step? Please, I didn't understand this.
Aishwarya said:
1 decade ago
How is it 37/4 in the first step?
Vinod kumar pattnaik said:
1 decade ago
As given in question we know that.
A watch gains 5 seconds in 3 minutes.
Its means covert 3 min into seconds4.
(3 x 60) = 180 sec (1 min = 60 sec).
Question tells 5 seconds gain.
It means for 180 sec it will become 180 + 5 = 185 seconds.
Right time is 180 seconds wrong time is 185 seconds.
Difference between true time and wrong time is 7 am to 4. 15 pm is 9 hours 15 min.
(9 x 60 = 540 + 15 = 555 min).
For 180 - 185.
? - 555.
(180 x 555) /185 = 540 in sec convert into min I. E 540/60 = 4 min.
A watch gains 5 seconds in 3 minutes.
Its means covert 3 min into seconds
(3 x 60) = 180 sec (1 min = 60 sec).
Question tells 5 seconds gain.
It means for 180 sec it will become 180 + 5 = 185 seconds.
Right time is 180 seconds wrong time is 185 seconds.
Difference between true time and wrong time is 7 am to 4. 15 pm is 9 hours 15 min.
(9 x 60 = 540 + 15 = 555 min).
For 180 - 185.
? - 555.
(180 x 555) /185 = 540 in sec convert into min I. E 540/60 = 4 min.
Rajasekar said:
1 decade ago
3M = 5s.
60M = 100s.
9H = (9 * 60m) = (9 * 100s) = 900s.
15M = 25s.
900S + 25s = 925s.
925S / 60s = 15.4m.
So, 15.4 is faster.
So reduce the faster value in actual value.
4.15m - 0.15m = 4h.
60M = 100s.
9H = (9 * 60m) = (9 * 100s) = 900s.
15M = 25s.
900S + 25s = 925s.
925S / 60s = 15.4m.
So, 15.4 is faster.
So reduce the faster value in actual value.
4.15m - 0.15m = 4h.
Shivam said:
1 decade ago
@Dedeepya.
We can't go with the process you suggested because;
Let us take the correct time be 'x'.
Now as we already know that 'x' will be lesser than 4 : 15.
Now the mistake in your idea is you are taking x as 4:15 which means in another (4 : 15 - x) the error clock will gain (4 : 15 - x) * 3s, which you are not considering.
Kindly take 'x' instead of 4 : 15 and solve again you will definitely land into a correct answer.
We can't go with the process you suggested because;
Let us take the correct time be 'x'.
Now as we already know that 'x' will be lesser than 4 : 15.
Now the mistake in your idea is you are taking x as 4:15 which means in another (4 : 15 - x) the error clock will gain (4 : 15 - x) * 3s, which you are not considering.
Kindly take 'x' instead of 4 : 15 and solve again you will definitely land into a correct answer.
Praveen said:
1 decade ago
Thank you very much @Sundar.
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