Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 3)
3.
A clock is started at noon. By 10 minutes past 5, the hour hand has turned through:
145°
150°
155°
160°
Answer: Option
Explanation:

Angle traced by hour hand in 12 hrs = 360°.

Angle traced by hour hand in 5 hrs 10 min. i.e., 31 hrs = 360 x 31 ° = 155°.
6 12 6

Discussion:
87 comments Page 8 of 9.

Leenus said:   1 decade ago
I can't understand "by 10 mins past 5".

Madesh said:   1 decade ago
Don't worry I will explain Clearly....

Past 5 means 5 hours.. and 10 mins out of 60 mins.. that's (10/60)

So.. 5hrs + 10 mins= 5+(10/60) = 5+(1/6).. so. 6*5+1= 31/6hrs..

1hr= 30 degree... so 5hrs= 150 degree and that past 5(means 5degree)...

So 150+5 = 155.

Kranti said:   1 decade ago
Very nice explanatoin given by shravan.

Shravan purohit said:   1 decade ago
@navaneetha

Given : our hour hand started at noon i.e. 12 o'clock
and 10 minutes past 5 i.e. 5 hour 10 minutes
we find angle between 12 and 5.10 o'clock
firstly we convert 5hour 10min into minitus 5*60+10=310min
and 310min convert into hour 310/60=31/6

In 12h = 360
So in 31/6 h= (360/12)(31/6)=155 degree.
(1)

Vinay said:   1 decade ago
It is for 5 hours 10 minutes from noon (12).

Navaneetha krishnan said:   1 decade ago
Sir i can't understand that 155 degree for which timing?

Narendran, S S said:   1 decade ago
Angle between hr and min is given by

A =30*hr~(11/2)*min
= 30*5 - (11/2)*10
= 95 degrees

Now the angle swiped by the min hand alone is

6 degrees per min
hence 60 degrees per 10 min

Angle swiped by hr hand alone is
A+60 = 95+60 = 155 degrees.

Resham said:   1 decade ago
Initially both hands are at 12(noon)
1 hr= 30 dgrs ( 12 to 5 = 5 hrs)
so 5*30 = 150 dgrs and
in 60 mins cover 30 dgrs
in 10 mins= 30/60
in 1 min= 30/60*10= 5 dgrs
so
150 + 5 = 155 dgrs

Naveed Mohammad said:   1 decade ago
Formula for finding degree when min and hr ar given is

angle = (11/2)*m - 30*h when (11/2)*m > 30*hr
angle = 30*hr-(11/2)*m when (30hr > (11/2)*m

where m = min, hr = hours

=30*5-(11/2)*10
=150-(120/2)
=(300-120)/2
=180/2
=90 degrees

Its a time institute materiel solution.

Akshay said:   1 decade ago
10min past 5 is 5:10
so, 5+10/60 =5+1/6(cross multiply)=31/6


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