Aptitude - Clock - Discussion

Answer is very simple.

Difference between the hour hand and minute hand is 60 deg but for every minute hour hand will move by 1/2deg and for 15 min hour hand is moved by 7.5 deg so total is 60+7.5 = 67.5 deg.

Find the angle of the hands at 12:40?

15 minute past 5.

Time is - 5.15.

In minute hand at 15 minute = 60 degree.

In hour hand at 15 minute.

Here each 1 mint the hour hand change. 5 degree.

So, at 15 m hour hand change = 15*.5 = 7.5 degree.

So, total degree is = 60+7.5 = 67.5 degree.

21/4 = 5 hr 15 min = 5(15/60) = 5(1/4) = ((5*4)+1)/4 = 21/4.

@Sagar.

If 5+15/60, then why again 15 minutes is considered separately and solved in the answer?

5+15/60 = 21/4 is correct.

Total no of points between any two no in watch for hour is 6. And for minute is 5.

Then angle between any two points for hour is 5 degree. And such for minute is 6 degree.

So when hour needle move one point between any two no then minute needle move 6 degree so the angle between any two no like 4 to five be 30 degree.

So cover 5 degree (for hour) = 10 degree (for min).
So 1 degree = 2 degree.

So when min needle travel 1 degree then hour needle cover 1/2 degree.
So for 15 minute it will cover 15/2 = 7.5.

And degree from 3 to 5 be 60 degree.
So total = 60+7.5 = 67.5.

Using formula to calculate angle i.e. 1/2(60*h-11*m) where h is hour time and m is minute, angle can easily be calculated.

What is past 5? which means what?

Theta = 1/2(60*h-11*m) (formula).

Where h = hour and m = minute.

5.15 = 1/2(60*5-11*15).

= 1/2(300-165).

= 67.5.