Aptitude - Clock - Discussion
Discussion Forum : Clock - General Questions (Q.No. 7)
7.
At what time between 5.30 and 6 will the hands of a clock be at right angles?
Answer: Option
Explanation:
At 5 o'clock, the hands are 25 min. spaces apart.
To be at right angles and that too between 5.30 and 6, the minute hand has to gain (25 + 15) = 40 min. spaces.
55 min. spaces are gained in 60 min.
| 40 min. spaces are gained in |  |
60 | x 40 |  min |
= | 43 | 7 | min. |
| 55 | 11 |
 Required time = 43 |
7 | min. past 5. |
| 11 |
Discussion:
76 comments Page 5 of 8.
Modon said:
1 decade ago
@Chandra Shekar.
At 12 pm both hour and second hands are in the same line. If it is 1 pm the hour hand is at 1 and minute hand at 12. So difference is 5 mins.
We can say, reach 1 from 12 (hour hand) needs 60 mins but space difference is 5 mins. So in 60 mins 55 mins space covered.
At 12 pm both hour and second hands are in the same line. If it is 1 pm the hour hand is at 1 and minute hand at 12. So difference is 5 mins.
We can say, reach 1 from 12 (hour hand) needs 60 mins but space difference is 5 mins. So in 60 mins 55 mins space covered.
Akshi panwar said:
1 decade ago
15 minutes is added because perpendicular in clock is at 15 min.
After every 15 min gap between hour hand and min hand there will be a 90 degree angle is formed.
After every 15 min gap between hour hand and min hand there will be a 90 degree angle is formed.
Ramkant said:
1 decade ago
Why the 15 min extra is added?
Jeyamani said:
1 decade ago
Actually the question is between 5.30 & 6.00. But you have taken from 5.00. Why?
Vaibhav patil jadhav said:
1 decade ago
Hi guys,
Here either of the formulas can be applied but the thing is the angle must not be negative you definitely gets the answer.
Theta = 11/2(min)-30(hrs)...or theta = 30(hrs)-11/2(min).
Good luck.
Here either of the formulas can be applied but the thing is the angle must not be negative you definitely gets the answer.
Theta = 11/2(min)-30(hrs)...or theta = 30(hrs)-11/2(min).
Good luck.
Vaibhav patil jadhav said:
1 decade ago
@Priya.
We can't write 5:30 as (5+1/2)hrs bcoz it is written 5 hrs from 5 to 6 o'clock....we automatically find the minutes where they both meet using the formula theta = 11/2(min)-30(hrs) as the angle is less than 180.
We can't write 5:30 as (5+1/2)hrs bcoz it is written 5 hrs from 5 to 6 o'clock....we automatically find the minutes where they both meet using the formula theta = 11/2(min)-30(hrs) as the angle is less than 180.
Vaibhav patil jadhav said:
1 decade ago
If the hours are less than 6 or the angle less than 180 then use...theta =11/2(min)-30(hrs).
If the hours are greater than 6 or the angle greater than or equal to 180 then use...theta = 30(hrs)-11/2(min).
It's simple and helps a lot. Good luck.
If the hours are greater than 6 or the angle greater than or equal to 180 then use...theta = 30(hrs)-11/2(min).
It's simple and helps a lot. Good luck.
(2)
Priya said:
1 decade ago
Why you are consider 5 while given time is 5:30?
Prithish said:
1 decade ago
Instead of only taking 25+15 we can also take 25-15, that will also be a right angle.
Margaret said:
1 decade ago
If we consider the basic solution, and start at 5:30 then min. space between hands at that time is 5 spaces and we need 10 more spaces to get right angle.
So simply (60*10)/55 min past 5:30 i.e. 30 min.+(60*10)/55 min. past 5.
What is wrong in the solution?
So simply (60*10)/55 min past 5:30 i.e. 30 min.+(60*10)/55 min. past 5.
What is wrong in the solution?
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