## Tuesday, November 3, 2009

### GMAT/CAT PREPARATION EMAIL COURSE DAY 17

CLOCKS:

Clock angle problems relate two different measurements - angles and time.
To answer the problem the relationship between the time and the angle between the hands .

-->A dial of the clock is divided into 60 parts each called minute spaces.
-->The hour hand goes 5 minute spaces in one hour and minutes hand goes 60 minute spaces in one hour.
-->Thus the minute hand covers 6 degress per minute.
-->The hour hand covers 30 degrees per hour.
-->The minute hand gains 55 minute spaces over the hour hand in one hour
-->When two hands are in 90 degree they are 15 minute spaces apart. This occurs twice in an hour.
-->When the two hands are in opposite directions(ie,180 degrees)they are 30 minute hands apart this occurs once in an hour
-->Two hands are in straight line when they coincide or are in opposite directions
-->The angle between the two hands = 6(x-11/12m)
X= hour hand convert into minute spaces i.e.* 5 of the earlier clock
M = the later part of the time i.e. minutes