what is the youngest this person can be?

Question

Martha said: “I have been alive for all or part of five decades.” Rounded to the nearest year, what is the youngest she could be?

How can this be solved?

Answer 1

The answer is 30.

If someone was born December 30, 1979 and passed Jan 2nd, 2010 then they will have lived 30 years and in part of 5 decades (with e.g., the 70s beginning in Jan 1st 1970 and ending Dec 31st, 1979).