Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 15)
15.
At what time between 9 and 10 o'clock will the hands of a watch be together?
45 min. past 9
50 min. past 9
49 1 min. past 9
11
48 2 min. past 9
11
Answer: Option
Explanation:

To be together between 9 and 10 o'clock, the minute hand has to gain 45 min. spaces.

55 min. spaces gained in 60 min.

45 min. spaces are gained in 60 x 45 min or 49 1 min.
55 11

The hands are together at 49 1 min. past 9.
11

Discussion:
47 comments Page 1 of 5.

Sivanandhini chandrasekar said:   8 months ago
Formula :
Θ = |11M/2 - 30H|.
0⁰=|11M/2 - 30*9|.
= 11M/2 - 270.
0⁰+270⁰=11M/2.
270*2/11=M.
540/11=M.
M = 49 1/11.
(4)

Nikhil B said:   4 years ago
@All.

θ = (11m/2) - 30h is a standard formula.
(4)

Akhilesh said:   8 years ago
My solution is:

Both the hands will meet somewhere between 9 and 10 i.e after the minute hand has reached 9 ( after 45 minutes). In these 45 mins the hour hand must also have traveled forward by some angle.

The angles covered by the hour hand in 45 mins will be 22.5. (how? in one min it covers 1/2 that's why!).

Now, let's suppose it takes another x mins for both of them to reach the point where they will coincide.
The angle traveled by hour hand will be x/2 and by the minute hand will be 6x.

Now in order to coincide with the hour hand, the minute hand has to cover the total angle the hour hand has moved forward.

So, 6x = x/2 + 22.5.
(3)

Niraj kumar said:   10 years ago
When the hands of watch together at that time it is obvious that angle made by hour's hand = angle made by minute's hand.

Let us assume both hand meet at time (9+x/60), where x = minute.

Now, (9+x/60)*360/12=x*360/60 (angle made by both hand).

After solving this equation, we find x=540/11. So ans=9hr, 540/11min. i.e = Option C.
(2)

Saranya said:   2 years ago
55 = 60 min.
45 = x.
X= 60*45\55.
X = 540/11.
X = 49 1/11 past 9.
(1)

Vinayak said:   6 years ago
How does 60/55*45 become 49 1/11?

Please if anybody can explain this?
(1)

Aarthi said:   9 years ago
Can you tell me the correct explanation?

Suman said:   3 years ago
Thanks for explaining @Akhilesh.

Abhishek said:   9 years ago
@Kapil.

Awesome man done in the most basic way manner as possible. Really appreciate your work.

Smita said:   9 years ago
Past 9n means?


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