Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 5)
5.
How much does a watch lose per day, if its hands coincide every 64 minutes?
32 8 min.
11
36 5 min.
11
90 min.
96 min.
Answer: Option
Explanation:

55 min. spaces are covered in 60 min.

60 min. spaces are covered in 60 x 60 min. = 65 5 min.
55 11

Loss in 64 min. = 65 5 - 64 = 16 min.
11 11

Loss in 24 hrs = 16 x 1 x 24 x 60 min. = 32 8 min.
11 64 11

Discussion:
119 comments Page 12 of 12.

HIMANSHU DEWANGAN said:   1 decade ago
It is universal truth that watch does not lose any time.Every day start from 12:00 am in night, hr. and min hand positioned at 0 degree,than how lose? no lose is there..

But suppose hands coincide every 64 min.
(In really it is not possible..eg if ones they coincide it take 65+5/11 min always for next)
there will be lose of 65+5/11 - 64= 16/11 from actual or real time in 65+5/11 min.

So calculate lose in 1 day= 24*60 min

Karthik said:   1 decade ago
How can the watch lose time if it is covering earlier than what is expected?

MADDY said:   1 decade ago
To coincide with each other space(ticks) between them should be ZERO(no space).

Consider starting from 12 noon.

in 1 hr--> min hand covers spaces(ticks) =60
in 1 hr--> hour hand covers spaces(ticks) = 5
so in 1 min --> hour hand covers 5/60=1/12 space(tick)

so after 1 hr=60 mins (1.00) spaces between them will be equal to 5
so have to cover 5 places for minute hand to meet hour hand
total time = 60+5 ... but in 5 mins hour hand will further go ahead by 5*1/12 ticks
so have to cover 5/12 ticks for minute hand to meet
total time = 60+5+5/12 ... but agin in 5/12 mins hour hand will go ahead buy 5/12*1/12= 5/12^2... and so on

So total time will be = 60+5+(5/12+5/12^2+5/12^3+.........) this GP
total time to meet = 720/11 i.e., 65.(5/11).

This time required to coincide hands in correct clock... solve accordingly.
(1)

Sharat said:   1 decade ago
What is this min. space?

Does it mean the min. hand lags the hour by 5 min. space ?

Priya said:   1 decade ago
How 55 spaces in 60 mins? couldnt get that.

Soumya said:   1 decade ago
Why we multiply 1/64 ?

Tarak B Patel said:   2 decades ago
Solution:

In 1 hour both the hands cover 55 min space.
=> 60/55 = 12/11 min space covered in 1min of the actual time.

for the hand to coincide hands have to cover 60 min space
=> 12/11 * 60 = 720/11 = 65.5/11 min in actual clock.

But the clock coincides every 64 min.
=>65.5/11 - 64 = 1.5/11 = 16/11 min loss in 64min.
=>16/11 * 1/64 = 1/44 min loss in 1min.

Loss In 24 Hrs => 1/44 * (24 *60) = 360/11 = 32.8/11 min the clock looses in a day.
(3)

Ravi said:   2 decades ago
I can't understand this: (60/55*60) why this step is used. Please someone explain me?

K.kiran kumar said:   2 decades ago
I cant get the question what it means. Please someone try to explain it.


Post your comments here:

Your comments will be displayed after verification.