Tips and Tricks for Calendar | Logical Reasoning (LR) and Data Interpretation (DI) - CAT PDF Download

Tricks to Solve CAT Calendar Questions

Finding Day of a Date by Using a Reference Date

• We will be using the days method. 
• The number of excess days is used to calculate the number of days the calendar has moved by. 
• 1.1.1973—Tuesday

Due to 1973, the calendar will go ahead by 1 day, similarly, due to 1974—1 day, due to 1975—1 day, and due to 1976—2 days. So, in four years, the calendar will go ahead by 5 days.

• Using the unitary method, in four years, the calendar will move ahead by 5 days.
• So, in 24 years, the calendar will move ahead by 30 days. Hence, the calendar will move ahead by 2 days.
• So, 1.1.1997 will be two days ahead of Tuesday, that is, Thursday.

Through Manual Calculation

You have to memorize the code table for this method.

Example: Find the date of 15th August 1947

• Add the Date + Month code of August + Last two digits of year + (Last two digits of year/4)
• [x] represents the greatest integer value of x
• So, corresponding to 15th August 1947—15 + 3 + 47 + 11 = 76
• Now, divide this value by 7 to find out the remainder.
• If the remainder is 0 then it is a Saturday.
• If the remainder is 1 then it is a Sunday.
• If the remainder is 2 then it is a Monday.
• If the remainder is 3 then it is a Tuesday.
• If the remainder is 4 then it is a Wednesday.
• If the remainder is 5 then it is a Thursday.
• If the remainder is 6 then it is a Friday.
• Here, remainder is 6, so 15th August 1947 was a Friday.
• It should have been a ‘Free Day.)

Solved Examples

Q1: If every seconds Saturday and all Sundays are holidays in a 30 days month beginning on Saturday, then how many working days are there in that month ? (Month starts from Saturday)
(a) 25
(b) 22
(c) 24
(d) 23
Ans: (d)
As month begins on Saturday, so 2nd, 9th, 16th, 23rd, 30th days will be Sundays. While 8th and 22nd days are second Saturdays. Thus, there are 7 holidays in all.
Hence, no. of working days = 30 – 7 = 23.

Q2: The calendar for the year 1988 is same as which upcoming year?
(a) 2012
(b) 2014
(c) 2016
(d) 2010
Ans: (c)
We already know that the calendar after a leap year repeats again after 28 years.
Here 1988 is a Leap year, then the same calendar will be in the year = 1988 + 28 = 2016.

Q3: What was the day of the week on 16th August, 1947?
(a) Sunday
(b) Monday
(c) Saturday 
(d) Thursday
Ans: (c)
15th August, 1947 = (1946 years + Period from 1st Jan., 1947 to 15th )
Counting of odd days:
1600 years have 0 odd day. 300 years have 1 odd day.
47 years = (11 leap years + 36 ordinary years)= [(11 x 2) + (36 x 1) ]odd days = 58 odd days = 2 odd days.
Jan  Feb  Mar  Apr  May  Jun  Jul  Aug.
31 + 28 + 31 + 30 + 31 + 30 + 31 + 15 = 227 days = (32 weeks + 3 days) = 3,
Total number of odd days = (0 + 1 + 2 + 3) odd days = 6 odd days.
Hence, the required day was 'Saturday'.

Q4: The calendar of the year 2024 can be used again in the year?
(a) 2030 
(b) 2052
(c) 2048
(d) 2036
Ans: (b)
Repetition of leap year ===> Add +28 to the Given Year.
Repetition of non leap year
Step 1: Add +11 to the Given Year. If Result is a leap year, Go to step 2.
Step 2:  Add +6 to the Given Year.
Given Year is 2024, Which is a leap year.
So, Add +28 to the given year (i.e. 2024 + 28) = 2052
Therefore, The calendar of the year 2024 can be used again in the year 2052.

Q5: The second day of a month is Sunday, What will be the last day of the next month which has 31 days?
(a) Friday
(b) Saturday
(c) Sunday
(d) Can't be determined
Ans: (d)
We cannot find out the answer because the number of days of the current month is not given.