If it was Saturday on January 1, 2000, then January 1, 2001, would have been:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Monday
The weekday repeats every 7 days, so only the odd days left over after whole weeks move it forward. From 1 January 2000 to 1 January 2001 is the whole of the year 2000.
2000 is divisible by 400, so it is a leap year with 366 days
366 days \(=52\) weeks + 2 days, so there are 2 odd days
1 January 2001 \(=\) Saturday + 2 days \(=\) Monday
Tip: A century year is a leap year only if it is divisible by 400: 2000 was a leap year, but 1900 and 2100 are not. Treating 2000 as an ordinary year would give 1 odd day and the wrong answer, Sunday.