If a person lived for eighty years how often during his life would Christmas day fall on a Sunday..

if he is 80 years old now, he was born in 1931.
from 1932 up to 2011 there are 13 times that Christmas fall on a Sunday.
1932, 1938, 1949, 1955, 1960, 19166, 1972, 1977, 1983, 1988, 1994, 2005, 2011

13 times--->>>>Answer

Christmas is on a Sunday once every 7 years EXCEPT when a leap year occurs when the day would normally fall on a Sunday as it will push it from Saturday to Monday.

This will happen when n*7 is divisible by 4. This is at 28 and 56.

So approx 80/7 - 2 = 11 - 2 = 9 times

Need more details. Answer would depend on when his birthday is, so that you could calculate how many leap years there are in the person's life span. Then calculation would be easier.

I seriously have nooo clue.

14 times if this year the person's age is 80