Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 16)
16.
At what time, in minutes, between 3 o'clock and 4 o'clock, both the needles will coincide each other?
5 1 "
11
12 4 "
11
13 4 "
11
16 4 "
11
Answer: Option
Explanation:

At 3 o'clock, the minute hand is 15 min. spaces apart from the hour hand.

To be coincident, it must gain 15 min. spaces.

55 min. are gained in 60 min.

15 min. are gained in 60 x 15 min = 16 4 min.
55 11

The hands are coincident at 16 4 min. past 3.
11

Discussion:
33 comments Page 3 of 4.

Prawesh Pradhan said:   8 years ago
m= 60/11 * t,
m= 60/11 * 3.
m= 16 4/11.

Raju said:   8 years ago
Let M for a minute, T1 for the starting hour and Y for a nangle.

Then the formula be M= 2/11(T1*30- 0r + Y).
2/11(3*30+-0) because coincide means angle is zero.
2*90/11.
180/11.
16 4/11 answer.

Harshitha said:   7 years ago
Thanks to all for explaining, I understand the answer.

Sumi said:   6 years ago
Thanks all for explaining.

Mohan said:   6 years ago
How 15 min space comes? if we consider 3 o clock. Please explain.

Nancy said:   6 years ago
How to find 15min space?

Grump said:   6 years ago
Here, min space refers to the displacement of the minute hand, w.r.t y o' clock, in forms of mins(minute hand mins) where y = 3.

So min space = 15(5, 10, 15 - 1, 2, 3)

Visualize relative speed. There are two trains. One is goods train 15 km away travelling at 5/60 km per min.

And there is another train which is travelling at 1 km per minute.

Relative speed = (1-5/60)kmph.

= 55/60 = 11/12.

time = distance/speed = 15/(11/12)min = 180/11 min = 16 + 4/11 min.
(1)

Pavan said:   6 years ago
Thank you @sai.

Shruti said:   5 years ago
55 min is there because.

In one hour (60 min), the minute hand is 55 min ahead of the hour hand.

OVI said:   5 years ago
Can anyone explain briefly?
(1)


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