Odd Days: We are supposed to find the day of the week on a given date. For this, we use the concept of 'odd days'. In a given period, the number of days more than the complete weeks are called odd days.
Leap Year: (i). Every year divisible by 4 is a leap year, if it is not a century. (ii). Every 4th century is a leap year and no other century is a leap year. Note: A leap year has 366 days. Examples:
Each of the years 1948, 2004, 1676 etc. is a leap year.
Each of the years 400, 800, 1200, 1600, 2000 etc. is a leap year.
None of the years 2001, 2002, 2003, 2005, 1800, 2100 is a leap year.
Ordinary Year: The year which is not a leap year is called an ordinary year. An ordinary year has 365 days.
Counting of Odd Days:
1 ordinary year = 365 days = (52 weeks + 1 day.)
Therefore, 1 ordinary year has 1 odd day.
1 leap year = 366 days = (52 weeks + 2 days)
Therefore, 1 leap year has 2 odd days.
100 years => 76 ordinary years + 24 leap years => (76 x 1 + 24 x 2) odd days = 124 odd days. => (17 weeks + days) 5 odd days.
Therefore, Number of odd days in 100 years = 5.
Number of odd days in 200 years = (5 x 2)3 odd days.
Number of odd days in 300 years = (5 x 3)1 odd day.
Number of odd days in 400 years = (5 x 4 + 1)0 odd day.
Similarly, each one of 800 years, 1200 years, 1600 years, 2000 years etc. has 0 odd days.
Day of the Week Related to Odd Days:
0 - Sun
1 - Mon
2 - Tues
3 - Wed
4 - Thurs
5 - Fri
6 - Sat
face or dial of watch is a circle whose circumference is divided into
60 equal parts, called minute spaces
Hand and Minute Hand:A
clock has two hands, the smaller one is called the hour hand or short
hand while the larger one is called minute handor long hand.
60 minutes, the minute hand gains 55 minutes on the hour on the
every hour, both the hands coincide once.
hands are in the same straight line when they are coincident or
opposite to each other.
the two hands are at right angles, they are 15 minute spaces apart.
the hands are in opposite directions, they are 30 minute spaces
traced by hour hand in 12 hrs = 360°
traced by minute hand in 60 min. = 360°.
a watch or a clock indicates 8.15, when the correct time is 8, it
is said to be 15 minutes too fast.
the other hand, if it indicates 7.45, when the correct time is 8,
it is said to be 15 minutes too slow.