Understanding Dr. Johnson’s Age Riddle

The Scenario

The day before yesterday, Dr. Johnson was 30 years old. Next year, he will celebrate his 33rd birthday. How can this be?

The Explanation

Today is January 1. This means that yesterday, on December 31, Dr. Johnson celebrated his 31st birthday. Therefore, on the day before yesterday, he was still 30 years old. This year, on December 31, he will turn 32, and next year, he will reach the age of 33.