Aptitude - Clock - Discussion

11M-60H/2 = angle.

Here, M=minute, H=hour.

Formula:30(M/5-H)-M/2 if the minute hand is ahead of the hour hand.
30(H-M/5)+M/2 if the hour hand is ahead of the minute hand.

EXAMPLE: Angle for 4.15,
H=4 M=15.

Here we use the second formula because the value M/5 is less than the H.
= 30(H-M/5)+M/2,
= 30(4-15/5)+15/2,
= 75/2,
= 37.5.

Can anyone please explain me the calculation part of (360/12 *125/12)degrees?

Can anyone explain what is a reflex angle (definition)?

@Madhuri.

We need to calculate total angle made by hour hand in 125/12 hours.
In 12 hours, hour hand cover 360 degrees.
Therefore for 1 hour = 360/12 degrees.

To calculate angle cover in 125/12 hours we multiply it with 360/12.
That is 360/12 * 125/12.

Which is similar to 30 * 125/12 { since hour hand cover 30 degrees in one hour}.

If you use the formulae the answer would be simple.
Instead of confusing in theoretical way.
Formulae
If hrs>6,
30hrs-(11/2)*min=angle,
else if hrs<6,
11/2*min-30hrs=angle,

In this sum
hrs=10;min=25,
since hrs>6 use 1st formulae,
subtitute ; 30*10 - (11/2)*25=angle,
angle=162.5,
sincle they have asked reflex angle,
reflex angle =360-162.5=197.5(only for reflex angles).

Formulae 1 & 2 are mostly used in clock problems
if they ask what is the minute and gave right angle or opposite angle, substitue the angle as 90deg or 180deg and proceed the sum.

Hour : 10*30=300degre.
25*0.5or1/2=15.5,
+=312.5,
Minute : 25*6=150,
312.5-150=162.5,
360-162.5=197.5 answer.

10 * (25/60 hr) = 10 * (5/12)=(12 * 10+5)/12 = 125/12.

BEST ANSWER:

Short hand or hour hand = 360/12 = 30,
Long hand or minute hand= 360/60 = 6,
When 10.25 is the short hand in the clock then 10x30=300 and 25x30/60=12.5,
Adding this 300+12.5=312.5,
When 25 minute long hand is 25x6=150,
=360-[312.5-150]=197.5.

Reflex angle = 360-[(11/2)*m-30*hr],
=360-[(11/2)*25-30*10],
=360-[137.5-300],
=197.5.


Note: degree between hr and min hand shortcut formula : (11/2)m-30*hr.