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 2 of 7.

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)

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)

Bombiyah said:   5 years ago
The angle formed from 12 o'clock to 7 o'clock is 210°.

Use this formula:

2/11 (angle formed (+) or (-) 180°)
Add 180 when the clock hands coincide, subtract when they are not.
Since, not coincide subtract it,
=2/11(210 * 180°)
= 60/11 or 5 5/11.

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)

Bhushan suriya said:   6 years ago
(210-6a)+(30/60)a = 180.

I think this will be the perfect solution.

John said:   6 years ago
@Vivek Jain.

In 1 hr minute, min hand covers 60 min and hr hand covers 5 min. Comparing both minute hand gains 55 min in 1 hr.

Hir@nm@y said:   6 years ago
At first you multiple 1st hours by 5 (7*5=35),
Then you substitute 30 from the multiple values, (35-30=5),

5* 5/11 [by rules of (x* x/11)].

That's answer will 7: 5* 5/11

Arika said:   6 years ago
Please solve how to find between 8 &9 o'clock as the same process?

Sushma R said:   6 years ago
A=30H-5.5M.
Where A=180',
H=7,

Now,
180=30*7-5.5M,
30=5.5M,
M=300/55,
M=5*5/11.