Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 14)
14.
At what time between 4 and 5 o'clock will the hands of a watch point in opposite directions?
45 min. past 4
40 min. past 4
50 4 min. past 4
11
54 6 min. past 4
11
Answer: Option
Explanation:

At 4 o'clock, the hands of the watch are 20 min. spaces apart.

To be in opposite directions, they must be 30 min. spaces apart.

Minute hand will have to gain 50 min. spaces.

55 min. spaces are gained in 60 min.

50 min. spaces are gained in 60 x 50 min. or 54 6 min.
55 11

Required time = 54 6 min. past 4.
11

Discussion:
55 comments Page 2 of 6.

Nikita Agrawal said:   8 years ago
Somebody, please tell me the degrees of every direction.

Ajay Kumar said:   8 years ago
You explained very well. Thanks @Kiran.

Pratima said:   8 years ago
Between 4 and 5, the minute hand to move 20 min in right half of circle (watch) from the initial point that is 12 here.

And 30 minutes from 4 in another side to go in opposite direction. So total is 20+30=50.

Owen Wilson said:   8 years ago
What does it mean when it says "55 min. spaces are gained"?

Suman said:   8 years ago
As per my calculation, the correct answer will be 55.38 min.

Sainath said:   8 years ago
Use this formula:

(5n-30)*12/11 for n>6.
(5n+30)*12/11 for n<6.

Harsh said:   9 years ago
How its 55min?

Initially its 12:00am hour and min hand makes 0° after an hour i.e 1:00am hour hand travels 5 min and minute hand travels 60 min so difference between hour and min hand is 55 min.

Nitin said:   9 years ago
Use this formula that is Min=60/11 * (Hr+6)

If Hr 1 to 5 make addition
If Hr 6 to 12 make subtraction.

Like Q 4 to 5 clock in opposite directions case

Min = 60/11 * (4+6)
= 60/11 * 10
= 600/11
= 54 6/11. Min. Past.

Tejas said:   9 years ago
Its simple just crosscheck each option given, you will get the desired answer like,
for option A:

4:45
4 + 45/60 = 19/4.
360/12 * 19/4 = 285/2°.

And
360/60 * 45 = 270°.

Clearly,
285/2 - 270 = Not equal to 180° (exact opppsite angle) likewise crosscheck all options you will get option D as the right answer.
D:
4 + 600/11 * 1/60 = 54/11°.
360/12*54/11 = 1620/11°.
And
360/60 * 600/11 = 3600/11°.

Then,
3600/11 - 1620/11 = 180° (exact opposite angle).

Sowmi said:   9 years ago
At 5 O' clock, the minute hand is 25 min spaces behind the hour hand.

Case 1:

The minute hand is 6 min spaces behind of the hour hand.
In this case, the minute hand has to gain (25 - 6) = 19 minutes spaces,
55 min spaces are gained in 60 min, 19 min spaces are gained in [(19/55) * 60] = (20) 8/11 min.

Case 2 :

Minute hand is 6min spaces ahead of the hour hand
In this case, the minute hand has to gain (25 + 6) = 31 minutes spaces
55 min spaces are gained in 60 min, 31 min spaces are gained in [(31/55) * 60] = (33) 9/11 min.


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