How old are Carl Fredricksen and Charles Muntz in the movie UP?

This blog says:

There has been much speculation about the ages of Carl Fredricksen and Charles Muntz in Up. Many viewers of the film doubted that Charles Muntz could still be alive when Carl encounters him in the 2nd half of the film (after showing a grown up Muntz via newsreel footage when Carl is a child).  The following ages have been confirmed by director Pete Docter (via Lee Unkrich’s twitter).
At the beginning of the film, Carl is 9 years old and Charles Muntz is 23. So, when they meet later in the film, Carl is now 78 years old and Muntz is 92! It’s good to finally have that debate settled.

image from blog site listed above.