Which of the following pairs of years have identical calendars?
Show answer & explanation
Correct answer: B
Explanation
The calendar of a normal year repeats itself;
Divide the last two digits of the year by 4:
If the remainder is 1: 6 years later (e.g., 1981 ÷ 4 → remainder 1, so 1981 + 6 = 1987)
If the remainder is 2 or 3: 11 years later
If the remainder is 0 (a leap year): 28 years later
Therefore, the calendars for 1981 and 1987 are identical.