Katie likes to pose puzzles for her grandchildren, Andrea and Brian, who are 14 and 11 years old, respectively. One day, the grandchildren asked Katie how long she and
Grandpa had been married. Katie said, “If you add Andrea's age to one-third of the
years we have been married, you will get the same result as adding one more than
the difference between Andrea's and Brian's ages to one-half the years we have been
married." How long have Grandpa and Grandma been married?