# Aptitude - Clock - Discussion

Discussion Forum : Clock - General Questions (Q.No. 12)
12.
The angle between the minute hand and the hour hand of a clock when the time is 8.30, is:
80°
75°
60°
105°
Explanation:

 Angle traced by hour hand in 17 hrs = 360 x 17 ° = 255°. 2 12 2

 Angle traced by min. hand in 30 min. = 360 x 30 ° = 180°. 60 Required angle = (255 - 180)° = 75°.

Discussion:
42 comments Page 1 of 5.

17/2 = 8.5 but 8hr 30min, so how it's came 17/2 ?

Why we use this? can any one tell me please?

Hi @ALL

We can write 8.30 as 17/2 hours.

Let me explain.

17/2 = 8.5 = 8 hours + 0.5 hours

= 8 hours + 1/2 hours

= 8 hours + 1/2 x 60 mins (.: 1 hour = 60 mins, Therefore, 1/2 hours = 30 mins)

= 8 hrs 30 min.

Therefore, we can write 8-hrs 30-min as 17/2.

While solving problems, make all numbers in vulgar fraction, it will be easy to solve problems quickly.

For example: 360/12 x 17/2 = ?

It is easy to solve. Have a nice day!

Shekhar bhakat said:   1 decade ago
Try this formula it can solve any tipe of clock related problem.

Angle b/w two handes of the clock= (11/2) *min-30*hr;.

8hr+30/60=17/2.

Marati Raju said:   1 decade ago
It is . . . . Very simple
by the Formula:
30H-[11/2]M
at 8.30
i.e 240-165=75degrees

I hope that every one understood this . . . . .

Nagmani Sinha said:   1 decade ago
We can use other formula too...
30h-6m
where:
H=total hours including minute parts...
m=minutes

in above qn it would be

30*17/2-6*30=255-180=75;

Hope its easier formula.

Hours hand should be calculated by considering
hours Hand -( 8 * 360/12)= 240 deg
Minutes Hand - ( 30 * 360/60) = 180 deg

Total angle b/w Hour and Min = 240 -180 = 60 deg.

This is Practically as per the clock system.