Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 6)
6.
At what time between 7 and 8 o'clock will the hands of a clock be in the same straight line but, not together?
5 min. past 7
 5 2 min. past 7 11
 5 3 min. past 7 11
 5 5 min. past 7 11
Explanation:

When the hands of the clock are in the same straight line but not together, they are 30 minute spaces apart.

At 7 o'clock, they are 25 min. spaces apart.

Minute hand will have to gain only 5 min. spaces.

55 min. spaces are gained in 60 min.

 5 min. spaces are gained in 60 x 5 min = 5 5 min. 55 11

 Required time = 5 5 min. past 7. 11

Discussion:
68 comments Page 1 of 7.

Tushar said:   1 year ago
To calculate the angle between hr hand and min hand.
we have formula ->> 30*Hours-11/2*minutes.

In the above question, they said that minute and hour hands are in one line but not together means Angel between them should be 180°.
:: 30 * 7 - 11/2 * x = 180°.
Then, x = 5.4545 ~5 + 5/11.
(25)

Rohit Joshi said:   5 months ago
As the clocks are in a straight line but not together, the angle formed by the hands of the clock will be 180.

Now, We know that Angle = |30*Hours - 11/2*Minutes|
Therefore, 180 = 30*7 * 11/2 * Minutes.
210 - 180 = 11/2 * Minutes.
30 = 11/2 * Minutes.
60/11 = Minutes.
55 * 5/11 = Minutes.
So, finally, the answer is D.
(5)

Santhoshi vempati said:   4 years ago
The angle between minute's hand hour's hand=30H-(11/2)M.
H = hours; M = minutes.

Given hour's and minute's is a straight line, so the angle is 180degrees.
180 = 30(7) - (11/2) * M,
M = 60/7 = 5 5/11,
So, the answer is 5 5/11min.past 7.
(5)

Mohit Sharma said:   3 years ago
Î¸ = { hour * 30 } diff { min * 11/2 } take difference between greater value and smaller value.

Now for the straight line, we know Î¸ = 180.

We can put all these values in the formula

Hour = 7
Î¸ = 180
min = ?

Î¸ = hour * 30 diff min * 11/2.
180 = { 7 * 30 } diff { min* 11/2}.
180 = { 210 } diff { min* 11/2},
min = 2/11 * 210-180,
min = 60/11.

which is equal to 5 5/11.
(3)

Tejasri Samala said:   5 years ago
The simple formula to find is;

1. [(5h-30)*12/11] for h>6.
2. [(5h+30)*12/11]for h<6.
(3)

Dara. Sai Madhukar said:   4 years ago
This question is solved by using formula.

A=30*HOUR -5.5*MINUTES.

Here we aer going to take A =180 degrees (straight line).
180=30*7-5.5*M.
M is minutes.
(1)

Rohit said:   5 years ago
The formula is 11/2min-30 hour.

Why are we reversing this formula in this question? Please tell me.
(1)

Joshua Thangliana said:   5 years ago
Degree= 30H - 5.5M.

straight line= 180 °
=> 180= 30*7 - 5.5M.
=> M= 60/11.
So, Answer= 7 hours 60/11 min.
(1)

Tehsin said:   6 years ago
I couldn't get it how 55 min required to gain 60 min spaces. I mean they are min spaces so why not 60 min spaces be in 60 min? please someone explain!
(1)

Jaanu said:   7 years ago
Use this formula to find angle :

Angle=((11/2)*minutes )-30* hour.

Between 7 and 8 means that the time would be something around 7. So consider 7 hours and x minutes.
180 = (11* x )/2 - 30 * 7.
210 - 180 = 11*x /2.
30 = 11*x /2.
30*2 = 11x,
60 = 11x,
X = 5.5/11.
That is 7 hours and 5 5/11 min.