If 17 December 2012 was Monday, then what was the day of the week on 18 November 2020?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. Wednesday.
Leap years: 2016, 2020 (2 leap years)
Normal years: 2013, 2014, 2015, 2017, 2018, 2019 (6 normal years)
Days contributed by each normal year = 365 days
Days contributed by each leap year = 366 days
Total days from 1 Jan 2013 to 31 Dec 2019:
(6 × 365) + (2 × 366) = 2190 + 732 = 2922 days
From 17 Dec to 31 Dec 2012, there are 15 days.
Since 2020 is a leap year, the days from 1 Jan to 18 Nov are:
Total days:
31+29+31+30+31+30+31+31+30+31+18=323 days31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 18 = 323 \text{ days}31+29+31+30+31+30+31+31+30+31+18 = 323 days
Compute the total days and find the remainder when divided by 7
15 + 2922 + 323 = 3260 days
Now, we divide by 7 to find the remainder:
3260÷7=465 quotient, remainder 5
Since 17 December 2012 was a Monday, we move 5 days forward:
Monday → Tuesday (1 day)
Tuesday → Wednesday (2 days)
Wednesday → Thursday (3 days)
Thursday → Friday (4 days)
Friday → Saturday (5 days)
Thus, 18 November 2020 was a Wednesday