Aptitude Calendar Sums



Aptitude Calendar Sums

Introduction

Are you interested in learning the aptitude calender sums for getting selected in an company? On the Nithra Jobs site, we have given calendar questions and answers, including formulas for easy understanding.

Formulas to use:

1. 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.

2. 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.

3. Ordinary Year:

The year which is not a leap year is called an ordinary years. An ordinary year has 365 days.

4. Counting of Odd Days:

i) 1 ordinary year = 365 days = (52 weeks + 1 day.) 1 ordinary year has 1 odd day.

ii) 1 leap year = 366 days = (52 weeks + 2 days) 1 leap year has 2 odd days.

iii) 100 years = 76 ordinary years + 24 leap years.

= (76 * 1 + 24 * 2) odd days = 124 odd days.

= (17 weeks + days) = 5 odd days. 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 * 4 + 1) 0 odd day.

Similarly, each one of 800 years, 1200 years, 1600 years, 2000 years etc. has 0 odd days.

5. Days of the week related to odd days

Sunday - 0

Monday - 1

Tuesday - 2

Wednesday - 3

Thursday - 4

Friday - 5

Saturday - 6


Solved Problems:

1. It was Sunday on January 1, 2006. What was the day of the week January 2, 2010?

Answer: Saturday

Explanation:


On 31st December, 2005 it was Saturday.

Number of odd days from the year 2006 to the year 2009 = ( 1 + 1 + 2 + 1 )

= 5 odd days

On 31st December 2009, it was Thursday. 1st January, 2010 it is Friday.

The 2nd January, 2010 it is Saturday.


2. What was the day of the week on 29th May, 2006?

Answer: Monday

Explanation:


28 May, 2006 = (2005 years + Period from 1.1.2006 to 29.5.2006) Odd days in 1600 years = 0

Odd days in 400 years = 0

5 years = (4 ordinary years + 1 leap year) = ( 4 * 1 ) + ( 1 * 2 )

= 4 + 2

= 6 odd days

(31 (Jan) + 28 (Feb) + 31(March) + 30(April) + 29 (May)) = 149 days 149 days = (21 weeks + 2 day)

= 2 odd day.

Total number of odd days = (0 + 0 + 6 + 2) = 8

= 1 week + 1 day

= 1 odd day

1 odd day = Monday

The day is Monday.


3. What was the day of the week on 18th June, 1998?

Answer: Thursday.

Explanation:


18th June, 1998 = ( 1997 years + Period from 1.1.1998 to 18.6.1998) Odd days in 1600 years = 0

Odd days in 300 years = (5 * 3) ( 100 years = 5 odd days )

= 15 days

= 2 week + 1 day

= 1 odd day

97 years has 24 leap years + 73 ordinary years. Number of odd days in 97 years = ( ( 24 * 2 ) + 73)

= 121

= 17 weeks + 2 days

= 2 odd days

(31 (Jan) + 28 (Feb) + 31(March) + 30(April) + 31 (May) + 18 (June) ) = 169 days

= 24 weeks + 1 day

= 1 odd day

Total number of odd days = ( 0 + 1 + 2 + 1 )

= 4 odd days

4 odd days = Thursday

The day is Thursday.


4. If 6th March, 2005 is Monday, what was the day of the week on 7th March, 2004?

Answer: Monday.

Explanation:


The year 2004 is a leap year. So, it has 2 odd days.

But, Feb 2004 not included because we are calculating from March 2004 to March 2005. So it has 1 odd day only.

The day on 6th March, 2005 will be 1 day beyond the day on 6th March, 2004. Given that, 6th March, 2005 is Monday.

6th March, 2004 is Sunday (1 day before to 6th March, 2005) So 7th March, 2004 is Monday.

The day is Monday.


5. It was Sunday on Jan 1, 2006. What was the day of the week Jan 1, 2010?

Answer: Friday

Explanation:


On 31st December, 2005 it was Saturday.

Number of odd days from the year 2006 to the year 2009 = (1 + 1 + 2 + 1) = 5 days. On 31st December 2009, it was Thursday.

Thus, on 1st Jan, 2010 it is Friday.

Conclusion

Make use of Nithra Jobs site to improve your knowledge in calender sums. Solve the problems regularly to get fluency in this topic.




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