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 6 of 8.
Yuvrajsinh said:
9 years ago
Friends please help me, I don't know this chapter.
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)
Ashu said:
8 years ago
How can you get 11/2 in the formula?
Can anyone help me? Please.
Can anyone help me? Please.
Arpita Saxena said:
8 years ago
I didn"t understand this solution. Can anyone please explain?
Jeet said:
8 years ago
At 5.30, Angle between hands is 15 degree and 75' more required to make a right angle. Relative angle made by hands is 11/2 ' in a minute.
We can assume in x min they cover remaining 75.
So 11/2 * x = 75.
x = 150/11 min.
So at 30 + 150/11 min, they make a right angle.
We can assume in x min they cover remaining 75.
So 11/2 * x = 75.
x = 150/11 min.
So at 30 + 150/11 min, they make a right angle.
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)
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)
Vijaya said:
8 years ago
I don't understand how, 15 m gain? please anyone explain it.
Saravana said:
8 years ago
How the calculation (60\55)*40 = 43*7/11?
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