100 years contain 5 odd days.(it includes leap years also)
2000 years contain 20*5=100 odd days
400,800,1200,1600,200 are leap years because these are divisible by 400 so another 5 odd days
whereas 100,200,300,500..etc are not leap years
total of 105 odd days
105/7=0
2000 Dec 31 is Sunday next day is Monday

The year 2006 is an ordinary year. So, it has 1 odd day.

So, the day on 8^th Dec, 2007 will be 1 day beyond the day on 8^th Dec, 2006.

But, 8^th Dec, 2007 is Saturday.

 8^th Dec, 2006 is Friday.

We cannot find out the answer because the number of days of the current month is not given.

Fridays of the month are on 2nd,9th,16th 23rdand 30th

On 1st of next month will be Saturday

So Saturdays will be on 8th,15th, 23rd 30th

On 31st it will be Sunday

But if the month is July The next month will have a different day on the last day

Further, if the month is February then also we will have a different answer.

Total number of odd days between the years 2002 and 2006 =

(2006 – 2002) + 1 = 5 odd days. The year 2004 is a leap year, it has two odd days. So, one extra odd day is added.

So, if it was Wednesday on March 1, 2006, it would be (Wednesday – 5) Friday on March 1, 2002.

(or)

If a particular date is on a specific date in a year, the same date would have been on the day before in the previous year. However, if the first year is a leap year, the difference in the number of years will be two.

So, if March 01, 2008, was a Saturday (leap year)
March 01, 2007 = Thursday
March 01, 2006 = Wednesday
March 01, 2005 = Tuesday
March 01, 2004 = Monday (leap year)
March 01, 2003 = Saturday
March 01, 2002 = Friday

The year 2007 is an ordinary year. So, it has 1 odd day.

1^st day of the year 2007 was Monday.

1^st day of the year 2008 will be 1 day beyond Monday.

Hence, it will be Tuesday.

Remember the leap year rule (Given in the formulas)
1. Every year divisible by 4 is a leap year if it is not a century.
2. Every 4th century is a leap year, but no other century is a leap year.

800,1200 and 2000 come in the category of the 4th century (such as 400, 800, 1200, 1600, 2000, etc).
Hence 800,1200 and 2000 are leap years.

700 is not the 4th century, but it is a century. Hence it is not a leap year

Mentioned month begins on a Saturday and has 30 days

Sundays = 2^nd, 9^th, 16^th, 23^rd, 30^th
=> Total Sundays = 5

Every second Saturday is holiday.
1 second Saturday in every month

Total days in the month = 30

Total working days = 30 – (5 + 1) = 24

Since each day of the week is repeated after 7 days.

After 133 days, it will be Thursday.

So one day before that would be Wednesday.

(or)

1 week = 7 days

So, In order to find 132 days after Thursday, we need to find the number of weeks in 132 days

Now if we divide 132 by 7 : Quotient = 18 and Remainder = 6

Here, Quotient shows a number of weeks and the remainder is the number of days. So, If today is Thursday we need to find the day after 18 weeks and 6 days :

So, after 18 weeks it will be Thursday itself and after 6 days of Thursday, It will be Wednesday.

So, Wednesday is the day that comes after 132 days if it is Thursday today.

Hence, Wednesday is the right answer.

June 17, 1991 = (1990 years + period from 01.01.1991 to 17.06.91)

⇒Odd days in 1600 years = 0

⇒Odd days in the next 300 years = 15 odd days (2 week + 1 odd day) = 1 odd day

90 years have 22 leap years + 68 ordinary years.

⇒Number of odd days in 90 years = 22*2 + 68*1 = 112 odd days (16 weeks + 0 odd day) = 0 odd day

Number of odd days from 01.01.91 to 17.06.91= Jan. (31) + Feb. (28) + March (31) + April (30) + May (31) + June (17) = 168 days

⇒168 days = 24 weeks + 0 odd days

Total number of odd days = 0 + 1 + 0+ 0 = 1 odd day

1 odd day represents Monday, so the given day was Monday.

The year 2004 is a leap year. It has 2 odd days.

 The day on 8^th Feb, 2004 is 2 days before the day on 8^th Feb, 2005.

Hence, this day is Sunday.

The number of days more than the complete weeks are called odd days in a given period.

1 ordinary year = 365 days = (52 weeks + 1 day)
Hence the number of odd days in 1 ordinary year= 1.
1 leap year = 366 days = (52 weeks + 2 days)
Hence the number of odd days in 1 leap year= 2.

100 years = (76 ordinary years + 24 leap years )
= (76 x 1 + 24 x 2) odd days = 124 odd days.
=> (17 weeks + 5 days)
≡ 5 odd days.
Hence the number of odd days in 100 years = 5.

Number of odd days—->Day of the week
==>0—->Sunday
==>1—->Monday
==>2—->Tuesday
==>3—->Wednesday
==>4—->Thursday
==>5—->Friday
==>6—->Saturday
The last day of a century cannot be Tuesday or Thursday or Saturday.
because 100 century consists of 5 odd days, which means Friday is the last day.
200 century consists of 3 odd days, which means Wednesday is the last day.
300 century consists of 1 odd day, which means Monday is the last day.
400 century doesn’t consist of any odd day.
the cycle continues, hence proof.

1995 is an ordinary year, it has 1 odd day. So, the first day of 1996 will be one day beyond Sunday, i.e. it will be Monday.

29th Feb, 2016 = Monday => 28th Feb, 2012 = Sunday
28th Feb 2017 = Tuesday (because 2016 is a leap year, there will be 2 odd days)
Therefore» Feb 28th, 2018 (Wednesday), Feb 28th, 2019 (Thursday), Feb 28th, 2020 (Friday), Feb 29th, 2020 (Saturday)
Or, Feb 29th to Feb 29th after 4 years, we have 5 odd days.
So, every subsequent birthday would come after 5 odd days.
2020 birthday – 5 odd days
2024 birthday – 10 odd days = 3 odd days
2028 birthday – 8 odd days = 1 odd day
2032 birthday – 6 odd days
2036 birthday – 11 odd days = 4 odd days
2040 birthday – 9 odd days = 2 odd days
2044 birthday – 7 odd days = 0 odd days. So, after 28 years, his birthday would fall on Monday.
The next birthday on Monday would be in the year 2072 (further 28 years later), the one after that would be in the year 2100. But we are told that she lives up to the year 2099.
So, there are 2 occurrences of his birthday falling on Monday – 2044 & 2072.