## The Present is a Point just passed – David Russel

Posted: May 21, 2010 in Br@!n Te@\$er\$
Tags: , ,

Men talk of killing time, while time quietly kills them.”  This is a famous saying by Dion.

Hey guyz this qn is about time & clock.

How many times in a day do both hands of the clock meet ??

Its a simple one.. but pls try to solve without using ur wrist watch 😉

1. Balaji JP says:

Minutes hand can make 360 degree in 60 minutes.
So speed of Minutes hand = 360/(60*60) = 1/10 degree/second
Hours hand can make 30 degree in 60 minutes.
So speed of Hours hand = 30/(60*60) = 1/120 degree/second

Both hands start from 12 o’clock. After an hour Minutes hand will be at 12 and Hours hand will be at 1. Minutes hand has traveled 360 degree. Now the distance between Hours hand and Minutes hand is 30 degree. When the Hours hand cross Minutes hand it would have crossed a distance of x+30 degree (x is the distance Hours hand has traveled in the mean time). Now equate the time taken by Minutes hand and Hours hand. 120 * x = 10 * (30+x). So x = 30/11. So it takes 360+(30+(30/11)) degrees for the Minutes hand and Hours hand to cross each other in a complete cycle. So in 24 hours (24 * 360 degrees), the Minutes and Hours hand will cross (24*360) / (360+(30+(30/11))) = 22 times.

• Murali Krishnan D says:

Congratz balaji,

Bingo!