1. What are Date Problems?
Date problems are based on the calendar, and the following types of questions are usually asked under this topic -
- How many days are there between the two days?
- What date is it after a certain number of days?
- If some date has so and so day of the week then What day is it on some other date?
To solve questions on this topic you need to know how the calendar works, let's dive into it.
A year has 365 days, except for leap years which have 366 days.
If the year is divisible by 4 then it is said to be a leap year except when the year is a century year (i.e. 1800, 1900) for which it should be divisible by 400.
Example:
Which among the years mentioned below are leap years?
i. 2020, ii. 2022, iii. 4300, iv. 1900, v. 1800, vi. 2000
Solution:
Among these years 4300, 1900, 1800, and 2000 are century years as they have two zeros at the end so we will be dividing them by 400, not 4.
i. 2020 is divisible by 4 so it is a leap year.
ii. 2022 is not divisible by 4 so it is not a leap year.
iii. 4300 is a century year which is not divisible by 400 so it is not a leap year.
iv. 1900 is a century year which is not divisible by 400 so it is not a leap year.
v. 2000 is divisible by 400 so it is a leap year.
In a year there are 12 months, number of days in the months is as follows
7 Months have 31 days - Jan, March, May, July, August, October, and December
4 months have 30 days - April, June, September, and November
Only February has 28 days except in leap years February has 29 days.
A week has 7 days i.e. Monday Tuesday, Wednesday, Thursday, Friday, Saturday, and Sunday. They are cyclic which means each of them repeats every 7 days.
Here is a calendar for the Month of August 2022, observe it carefully. If you select any day the repetition is after 7 days right?
So can you guess the day of the week on 2nd Sept 2022?
The month ends on 31st Aug which is a Wednesday and 2nd September is 2 days later so 2nd Sept 2022 must be a Friday.
Now try to work out the day of the week on 15th December 2022.
To work out this you may follow these steps
Step 1: work out the number of days between the dates -
There are 30 days in September and November and 31 days in October.
Number of days from 31st August to 15th December = 30 + 31 + 30 + 15 = 106
Step 2: Divide the number of days by 7 and work out the remainder -
106 ÷ 7 = 15 remainder 1
Step 3: Remainder is how many days you need to add more
As remainder is 1, we will add one day to Wednesday which is Thursday.
15th December is Thursday.
Example:
Solved Examples:
Example 1:
If May 23rd is a Monday, on what day of the week is July 2nd?
8 + 30 + 2 = 40
40 ÷ 7 = 5 rem 5
5 days ahead of Monday is Saturday, so the 2nd of July is Saturday.
Example 2:
If there are 5 Mondays, 5 Tuesdays and 5 Wednesdays in May, on what day of the week will June 1st fall?
There are at least 28 days in every month which adds up to 4 weeks.
In May there are 31 days so the remaining number of days in the month of May, if we exclude the 4 weeks that come in each Month, is
31 - (7 × 4) = 31 - 28 = 3
So there could be only 3 such days possible which occur 5 times in May, which are according to the question, Monday, Tuesday and Wednesday. 31st January is Wednesday, so 1 June will be Thursday.
Now let's try out some quiz questions and practice questions.
