Important Points and Shortcuts for Clock problems

• Clock formula: 11/12. This is a very important point for solving aptitude questions on clocks.

• As minute hand covers one full circle i.e. 360 degrees in one hour, that means it travels 360/60 = 6 degrees/min.

• An hour hand covers one part of the 12 major parts of the circle which means it covers 360/12 = 30 degrees in one hour i.e. it travels 30/60 = 1/2 degree per min.

• Now, the relative speed of the minute hand is 6 – 1/2 = 11/2 or 5.5 degrees. This 11/2 degrees will be useful in finding the angle between the two hands of the clock.

• The complete circle has a total of 360 degrees and in terms of minute spaces, it has been divided into 60 minutes spaces, which means each minute space represents 360/60 = 6 degrees.

• The complete circle has been divided into 12 equal bigger units also, which we call as hours. This further implies that every hour space covers a total of 360/12 = 30 degrees.

• The hour hand and minute hand meet once every hour. But in a 12 hour period, they meet 11 times.

• There is one angle of 180 degrees in every hour i.e. both the hands are in the straight line in the opposite direction, but in a twelve-hour period, it happens 11 times.

• There are 2 right angles every hour, but in a 12 hour period, there are 22 such angles.

• If the two hands are moving at the normal speeds, they should meet after every 65 5/11 min.

• Clock Aptitude Tricks -Short Cut - Between x and (x + 1) O’clock, the 2 hands will be ‘t’ min apart at (5x t) 12/11 past x.