The table below shows the day of the week that 1st January falls on from the year 1981 to 2000. Note that Day 1 of a week is a Monday and Day 7 is Sunday. There are 31 days in the month of January.
a) What number does the letter C represent ? (Ans : 3)
b) What number does the letter F represent ? (Ans : 7)
c) Which day of the week will 1st February 2012 fall on ? (Ans : Wednesday)
2003 - 1981 = 22 years
22/4 = 5 leap years (max) Leap year --> 366 days
22 x 365 + 5 =8035 days Account for leap years
8035 + 4 = 8039 Since 1 Jan 1981 is 4 (Thursday).
8039/7 = 1148 r 3
a) It was 3.
2006 - 1981 = 25 years
25/4 = 6 leap years (max)
25 x 365 + 6 + 4 = 9135
9135/7 = 1305 or 1304 r 7 Need to express with a remainder
b) It was 7.
2012 - 1981 = 31 years
31/4 = 7 leap years (max)
31 x 365 + 31 + 7 + 4 = 11357 days
11357/7 = 1622 r 3
3 --> Wednesday
c) It is Wednesday.