# My Grandson - Age Word Problem

by Andrew

(New York)

My grandson, my son (his father), and I share the same birthday. This year I remarked to

my son, “You know, of course, that today all three of our ages have become prime

numbers. But did you realize that for the last 17 years prior to this year, whenever your

age was a prime number, so was mine, and vice versa?”

“Yes,” he replied. “And 17 years from now, I will say to my son, “You know, for the last

18 years prior to this year, whenever your age was a prime number, so was mine, and

vice versa.”

How old are we?