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 2 of 8.
Appu said:
8 years ago
At 5:30, the hands are 55 mins apart.To get an angle 90 btw them space must 15 mins apart,
so, the space is 55-15=40.
therefore,60/55-40=43 7/11.
so, the space is 55-15=40.
therefore,60/55-40=43 7/11.
(2)
Sonam said:
7 years ago
Can you explain me the calculation of 43 7/11 min how it comes from (60/55*40) min?
(1)
MATH EXPERT said:
9 years ago
FORMULA :
Guess P = ANS .
(11/2) x (minutes) - 30 x (Hours) = 90 degree.
11/2 x P - 30 x 5 = 90,
P = 480/11= ANS.
Guess P = ANS .
(11/2) x (minutes) - 30 x (Hours) = 90 degree.
11/2 x P - 30 x 5 = 90,
P = 480/11= ANS.
(1)
A. M. said:
8 years ago
The given explanation doesn't consider the movement of the hour hand. Between 5:30 and 6, the hour hand will also have moved. Then the minute hand will need to cover a little more than (25 + 15) minutes' space.
(1)
Jack84 said:
8 years ago
@ALL.
Min=AO
Hour=OB
AOB=25 min apart
To get 90 degree= minutes has to travel another 15 min from 5 O'clock i.e. 5:40 so, 25+15=40 min.
OB i.e.hour hand travels only 5 min in 60 min so=60-5=55 min,
the rest is given by experts.
Min=AO
Hour=OB
AOB=25 min apart
To get 90 degree= minutes has to travel another 15 min from 5 O'clock i.e. 5:40 so, 25+15=40 min.
OB i.e.hour hand travels only 5 min in 60 min so=60-5=55 min,
the rest is given by experts.
(1)
Ragav said:
7 years ago
Why we can't use 30H - 5.5H = 90 formula?
30(11/2) - 5.5H = 90.
30(11/2) - 5.5H = 90.
(1)
ABI said:
5 years ago
55min spaces are gained in 60min. What it is, Can someone explain to me this?
(1)
Adi said:
10 years ago
Dear sir,
Please prove formula.
Please prove formula.
Prashanth said:
10 years ago
If the minute hand is present before hour hand then use theta = 11/2min-30hr.
Like that hour hand is before minute hand theta = 30hr-11/2hr.
Use it you will get exact solution.
Like that hour hand is before minute hand theta = 30hr-11/2hr.
Use it you will get exact solution.
Lakhan singh meena said:
9 years ago
Direct formula:
6*x - 90 = 30(y + x/60);
Where y = 5 hr.
So 6x = 30(5 + x/60) + 90;
x = 43(7/11)min. past 5.
6*x - 90 = 30(y + x/60);
Where y = 5 hr.
So 6x = 30(5 + x/60) + 90;
x = 43(7/11)min. past 5.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers